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Full text of "The Gas and Oil Engine"

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library 

or tbe 

IQntvereit? of TOsconstn 



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THE 

GAS AND OIL ENGINE 



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THE 



GAS AND OIL ENGINE 



BY 



DUGALD CLERK 



ASSOCIATE MEMBER OP THE INSTITUTION OP CIVIL ENGINEERS 

FELLOW OP THE CHEMICAL SOCIETY : MEMBER OP THE ROYAL INSTITUTION 

FELLOW OP THE INSTITUTE OF FATENT AGENTS 



EIGHTH EDITION, REVISED 



JOHN WILEY & SONS 

43 & 45 EAST NINETEENTH STREET 

NEW YORK 

1899 



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137924 

JAN 22 1910 

TK 

Or 
'4 



IflU^l 



PREFACE 



THE SIXTH EDITION. 



Many important changes have been made in the constructive 
details of gas engines since the first part of this work was pub- 
lished, and oil engines using heavy oil have become practicable 
motors, so that it has become necessary to bring the informa- 
tion in this book thoroughly up to date. In doing this the author 
thought it better to make additions rather than alterations on the 
original, and accordingly the first part of the book is retained in 
its original form, and two parts have been added : the second 
part deals with modern gas engines, both impulse-every-revolution 
and Otto cycle ; and the third part deals with the oil engine. The 
first part of the book thus remains in the form in which it is 
familiar to many engineers ; indeed, the author may say with truth 
all engineers interested in the gas engine throughout the world, 
because the book has been translated and published in German, 
and many parts extracted in French works, while it is largely used 
in America both by engineers and in the engineering classes of 
the Universities. 

In dealing with the various engines the author has drawn 
upon his personal experience of gas and oil engines, now extending 



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vi The Gas Engine 

over twenty years, and he has endeavoured to discuss the various 
points involved in a dispassionate manner, pointing out to the 
engineer the difficulties as well as the advantages peculiar to each 
construction or type. This is very necessary if moderately rapid 
advance is to be made, and it appears to the author most un- 
desirable to adopt the tone so often found in engineering literature 
of indiscriminate admiration of this or that firm's wonderful motor, 
when in reality the motor discussed in so far as it departs from 
standard practice is not an improvement, but the reverse. The 
author has accordingly freely criticised any. points which appear 
to him defective in the various engines. 

In this edition special attention has been paid to the oil 
engine, in view of its rapid rate of present development and the 
probability of its very extensive use for many new purposes, such 
as motor cars. Many engineers are now paying attention to the 
oil engine, to whom the subject is unfamiliar ; and in the hope of 
proving useful to such new men on the work, the author has gone 
carefully into the discussion of the chemical nature of petroleum 
and the different methods of vaporising heavy oils. 

In dealing with the oil engine the author has freely availed' 
himself of the careful experiments on oil engines by the engineers 
for the Royal Agricultural Society's Show at the Cambridge 
Meeting. The author has made many tests himself ; but as these 
were mostly made in the course of his professional work and were 
confidential, he has chosen for discussion the publicly made tests 
and descriptions rather than his personal tests. 

In concluding, the author expresses his thanks to the Council 
of the Institution of Civil Engineers for the use of illustrations 
from papers by Professor Unwin and Mr. J. E. Dowson, published 
in the valuable Minutes of the Institution, and also for extracts of 



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Preface to the Sixth Edition vii 

tests by Mr. Dowson, and tables by the author, also published in 
Institution papers. 

The author also thanks the various makers of gas and oil 
engines who have allowed him to test their engines for the 
purposes of this book, and who have lent him blocks ; among those 
makers are Messrs. Crossley Bros. Limited, J. E. H. Andrew 
& Co. Limited, T. B. Barker & Co., Tangyes, Limited, Robey 
& Co. Limited, Wells Bros., Hornsby & Sons, Fielding & Piatt, 
Mr. Peter Burt, and Mr. Bellamy of Andrew & Co. 

Many of the drawings for the book, however, have been made 
by the author's draughtsmen directly from the engines. 

In the Appendix the author has added a complete list of 
British gas and oil engine patents from 1791 to the end of 1893. 
All the English specifications from 1876, including this year, are 
in the author's possession, and he will be very pleased to freely 
allow those interested access to them. 

D. C. 
18 Southampton Buildings, Chancery Lane, 
London : June 1896. 



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PREFACE 

TO 

THE FIRST EDITION. 



In this work the author has endeavoured to systematise the know- 
ledge in existence upon the subject, and to explain the science 
and practice of the Gas Engine in a way which he hopes may be 
useful to the engineer. 

The historical sketch with which the book opens proves that, 
like other great subjects, the gas engine has long occupied men's 
minds. 

The first six chapters treat of theory, including the distin- 
guishing features of the gas engine method, classification, thermo- 
dynamics of the various types, and the chemical and physical 
phenomena of combustion and explosion. 

In the seventh chapter, standard engines illustrative of the 
different types are described, and tests from each engine for power 
and consumption of gas are given. The diagrams and efficiencies 
are shortly discussed, compared with theory, and the various sources 
of loss pointed out. 

The eighth chapter deals with typical igniting arrangements, 
and the ninth with governing gear and other mechanical details. 



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x Preface to the First Edition 

The tenth chapter briefly describes and discusses various 
theories which have been propounded concerning the action of 
the gases in the cylinder of the gas engine and in gaseous explo- 
sions. 

In the last chapter the great sources of loss of heat still 
existing in the best gas engines are discussed, with the object of 
pointing out the way still open for further advance. 

Many of the tests and most of the theoretical and practical 
discussion, result from the author's personal experience with the 
gas engine. 

In the chapter on thermodynamics the author is much indebted 
to the work of the late Prof. Rankine, and he has adopted, in 
treating of efficiency, some of the elegant formulae of Dr. Aim£ 
Witz, of Lille, to whom as well as to Prof. Schottler and Prof. 
Thurston he has much pleasure in expressing his indebtedness. 

D. C 
Birmingham : Jtdy 1886. 



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CONTENTS. 



PART I. 
THE GAS ENGINE UP TO THE YEAR 1886. 

CHAPTER HACK 

Historical Sketch of the Gas Engine, 1690 to 1886 . x 

I. The Gas Engine Method 23 

II. Gas Engines Classified 29 

III. Thermodynamics of the Gas Engine . . . . 36 

IV. The Causes of Loss in Gas Engines .... 72 
V. Combustion and Explosion . . • . . . . 79 

VI. Explosion in a Closed Vessel 95 

VII. The Gas Engines of the different Types in Practice 116 

VIII. Igniting Arrangements 202 

IX. On some other Mechanical Details .... 226 

X. Theories of the Action of the Gases in the Gas 

Engine 243 

XL The Future of the Gas Engine 260 

PART II. 
GAS ENGINES PRODUCED SINCE 1886. 

I. Gas Engines giving an Impulse for every Revolution 271 

II. Otto Cycle Gas Engines 297 



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xii The Gas Engine 

CHAPTER PACK 

III. The Production of Gas for Motive Power . . 354 

IV. The Present Position of Gas Engine Economy . . 375 



PART III. 

OIL ENGINES. 

I. Petroleum and Paraffin Oils 387 

II. Oil Engines 407 

III. The Difficulties of Oil Engines 462 

APPENDIX I. 

Adiabatic and Isothermal Compression of Dry Air . . . 475 
Various Analyses of Coal Gas 476 

APPENDIX II. 

Composition of Coal and Cannel Gases (Frankland) . . 478 

Data calculated from Frankland's Analysis . . . . 479 

Oxygen required for Complete Combustion of the Gases 
given in Frankland's Analysis 480 

List of British Gas and Oil Engine Patents from 1791 to 
1897 inclusive 481 

Name Index to Gas and Oil Engine Patents. . . .558 
GENERAL INDEX . 575 



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THE 

GAS ENGINE. 

HISTORICAL SKETCH OF THE GAS ENGINE. 

The origin of the gas engine is but imperfectly known ; by some 
it is dated as far back as 1680, when Huyghens proposed to use 
gunpowder for obtaining motive power. Papin, in 1690, continued 
Huyghens* experiments, but without success. The method used 
was a fairly practicable one. The explosion was used indirectly ; 
a small quantity of gunpowder exploded in a large cylindrical vessel 
filled with air, expelled the air through check valves, thus leaving, 
after cooling, a partial vacuum. The pressure of the atmosphere 
then drove a piston down to the bottom of the vessel, lifting a 
weight or doing other work. 

In a paper, published at Leipsic in 1688, Papin stated that, 
* until now all experiments have been unsuccessful ; and after the 
combustion of the exploded powder, there always remains in the 
cylinder about one-fifth of its volume of air.' 

The Abb£ Hautefeuille made similar proposals, but does not 
seem to have made actual experiments. These early engines 
cannot be classed as gas engines. The explosion of gunpowder is 
so different in its nature from that of a gaseous mixture that com- 
parison is untenable. The first real gas engine described in this 
country is in Robert Street's patent, No. 1983, 1794. It contains a 
motor cylinder in which works a piston connected to a lever, 
from which lever a pump is driven. The bottom of the motor 
cylinder is heated by a fire ; a few drops of spirits of turpentine 

B 



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2 The Gas Engine 

being introduced and evaporated by the heat, the motor piston 
is drawn up, and air entering mixes with the inflammable vapour, 
the application of a flame to a touch-hole causing explosion ; and 
the piston being driven up forces the pump piston down, so per- 
forming work in raising water. The details, as described, are 
crude, but the main idea is correct and was not improved upon in 
practice till very lately. 

Samuel Brown's inventions come next. His patents are dated 
1823 and 1826, Nos. 4874 and 5350. The principle used is in- 




A, Cover raised, vessel filling with flame. B and C, Covers down, vessels vacuous. 

Fig. i.— Brown's Gas-vacuum Engine, 1826. 

genious, and easily carried out in practice, but it is not economical, 
and it gives a very cumbrous machine for the amount of power 
produced. A partial vacuum is produced by filling a vessel with 
flame, and expelling the air it contains, a jet of water is thrown 
in and condenses the flame, giving vacuum. The atmospheric 
pressure thus made available for power is utilised in any engine of 
ordinary construction. 

Brown's apparatus consists essentially of a large upright cylin- 



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Historical Sketch of the Gas Engine 3 

drical vessel fitted on the top with a movable valve cover, of the 
whole diameter of the cylinder. The cover is raised and lowered 
from and to its seat by a lever and suitable gear at proper times. 
The gas supply pipe enters the cylinder at the bottom ; the 
cylinder being filled with air, and the valve raised, the gas 
cock is opened and the issuing gas lighted by a small flame 
as it enters the cylinder. The flame produced fills the whole 
vessel, expelling the air it contains ; the valve being now 
lowered and the gas supply shut off, the water-jet is thrown in 
and causes condensation. To keep up a constant supply of power, 
several of these cylinders are required, so that one at least may be 
always vacuous while the others are in the process of obtaining 
the vacuum. In the specification three are shown and three 
engines. The engines are all connected to the same crank-shaft. 
Notwithstanding this provision, the motion must have been 
irregular. The idea was evidently suggested by the condensing 
steam engine ; instead of using steam to obtain a vacuum flame is 
employed. Brown's engine, although uninteresting theoretically, 
is important as being the first gas engine undoubtedly at work. 
According to the ' Mechanics' Magazine,' published in London, a 
boat was fitted with one including a complete gas generating 
plant, and was run upon the Thames not for public use but only 
as an experiment. Another engine was made in combination 
with a road carriage ; it also ran in London. If these statements 
are to be relied upon, then Samuel Brown was a really great man 
and should be considered as the Newcomen of the gas engine ; in 
some points he achieved a measure of success not yet equalled by 
his successors. 

IV. Z. Wright, 1833, No. 6525. — In this specification the 
drawings are very complete and the details are carefully worked 
out The explosion of a mixture of inflammable gas and air acts 
directly upon the piston, which acts through a connecting rod upon 
a crank-shaft. The engine is double-acting, the piston receiving 
two impulses for every revolution of the crank-shaft. In appear- 
ance it resembles a high pressure steam engine of the kind known 
as the table pattern. The gas and air are supplied to the motor 
cylinder from separate pumps through two reservoirs, at a pressure 
a few pounds above atmosphere, the gases (gas and air) enter 



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4 The Gas Engine 

spherical spaces at the ends of the motor cylinder, partly displacing 
the previous contents, and are ignited while the piston is crossing 
the dead centre. The explosion pushes the piston up or down 
through its whole stroke ; at the end of the stroke the exhaust 
valve opens and the products of combustion are discharged during 




Fig. 2. — Wright's Gas-exploding Engine, 1833. 

the return, excepting the portion remaining in the spaces not 
entered by the piston. The ignition is managed by an external 
flame and touch-hole. The author has been unable to find 
whether the engine was ever made, but the knowledge of the 
detail essential to a working gas engine shown by the drawings 
indicates that it or some similar machine had been worked by the 



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Historical Sketch of the Gas Engine 5 

inventor. Both cylinder and piston axe water-jacketed, as would 
have been necessary in a double-acting gas engine to preserve the 
working parts from damage from the intense heat of the explosion. 
This is the earliest drawing in which this detail is properly shown. 
William Barnett, 1838, No. 7615. — Barnett's inventions as 
described in his specification are so important that they require 
more complete description than has been here accorded to earlier 
inventors. 

Barnett is the inventor of a very good form of igniting arrange- 
ment. The flame method most widely used at the present time 
was originated by him. 

Bamett is also the inventor of the compression system now so 
largely used in gas engines. The Frenchman, Lebon, it is true, 
described an engine using compression, in the year 1801, but his 
cycle is not in any way similar to that proposed by Barnett, or 
used in the modern gas engine. Barnett describes three engines. 
The first is single-acting, the second and third are double-acting ; 
all compress the explosive mixture before igniting it. In the first 
and second engines the inflammable gas and air is compressed by 
pumps into receivers separate from the motor cylinder, but com- 
municating with it by a short port which is controlled by a piston 
valve. The piston valve also serves to open communication 
between the cylinder and the air when the motor piston dis- 
charges the exhaust gases. 

In the third engine the explosive mixture is introduced into 
the motor cylinder by pumps, displacing as it enters the exhaust 
gases resulting from the previous explosion ; the motor piston by 
its ascent or descent compresses the mixture. Part of the com- 
pression is accomplished by the charging pumps, but it is always 
completed in the motor cylinder itself. 

In all three engines the ignition takes place when the crank is 
crossing the dead centre, so that the piston gets the impulse during 
the whole forward stroke. 

Fig. 3 is a sectional elevation of the first engine, showing the 
principal working parts, but omitting all detail not required for 
explaining the action. 

There are three cylinders containing pistons ; a is the motor 
piston, b is the air pump piston. The gas pump piston cannot be 



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6 The Gas Engine 

seen in the sectidn, but works in the same crosshead as b. The 
motor piston is suitably connected to the crank shaft, and the 
other two are also connected by -levers in such manner that all 
three move simultaneously up or down. The pump pistons, 
moving up, take respectively air and inflammable gas into their 




Fig. 3.— Barnett Gas Engine. 

cylinders ; upon the down stroke the gases are forced through an 
automatic lift valve into the receiver d, and there mix. When the 
down stroke is complete and the receiver is fully charged with the 
explosive mixture, the pressure has risen to about 25 lbs. per square 
inch above atmosphere. At the same time as the pumps are com- 
pressing, the motor piston is moving down and discharging the 



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Historical Sketch of ttie Gas Engine 7 

exhaust gases from the power cylinder; it reaches the bottom of 
its stroke just when compression is complete. The piston valve 
e then opens communication between the receiver and the motor, 
at the same time closing to atmosphere. The motor cylinder 
being in free communication with the receiver, the explosion of 
the mixture is accomplished by the igniting cock or valve f ; the 
pressure resulting actuates the motor piston during its whole up- 




Fig, 4> r-Bamett's Igniting Cock. 

ward stroke, the hot gases flowing through the port g precisely as 
steam would do. The volume of the receiver being constant, the 
pressure in the motor cylinder slowly falls by expansion, due to 
the movement of the piston, upon which work is performed, and 
by cooling, the pressure still existing in the cylinder when the 
stroke is complete depending on the ratio between the volume 
swept by the motor piston and the volume of the receiver. 



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8 The Gas Engine 

The down stroke again expels the products of combustion, the 
valve opening to atmosphere, while the compression again takes 
place. This cycle gives a single-acting engine. It is obvious that as 
the piston a does not enter the receiver it cannot displace the 
exhaust gases there. If means are not taken to expel these gases 
they must mix with the fresh explosive charge pumped in. 

It is very desirable that these gases should be as completely 
as possible discharged. An exhausting pump is described for 
doing this, but in small engines it adds an additional complication ; 
and so Barnett states that in some cases it may be omitted The 
exhaust gases do not so injuriously affect the action of small gas 
engines. 

The igniting valve is very ingenious. It is shown at Fig. 4, on a 
larger scale. A hollow conical plug a is accurately ground into 
the shell b, and is kept in position by the gland c ; the shell has 
two long slits d and e ; the plug has one port so cut that as the 
plug moves it shuts to the slit d before opening to e. In the 
bottom of the shell there is screwed a cover carrying a gas burner 
f, which may be lit while the port in the plug is open to the air 
through d. The external constant flame h lights it. So long 
as the plug remains in this position the internal flame continues 
to burn quietly. If the plug be now turned to shut to the outer 
air, it opens to the slit e, and as that contains explosive mixture 
it at once ignites. The explosion extinguishes the internal flame, 
but it is again lighted at the proper time when the plug is moved 
round. The valve acts well and is almost identical in principle 
with the flame-igniting arrangements of Hugon, Otto and Langen 
and Otto. 

Barnett's second engine is identical with his first except that 
it is double-acting, and therefore requires a greater number of 
parts. 

Barnett's third engine is worthy of careful description. Fig. 5 
is a vertical section of the principal parts. It is double-acting. 
It has three cylinders, motor, air-pump and gas-pump ; the air 
and gas pumps are single-acting, the motor piston is double- 
acting. The pumps are driven from a separate shaft, which is 
actuated from the main crank shaft by toothed wheels ; the wheel 
upon the pump shaft is half the diameter of that on the motor 



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Historical Sketch oft/ie Gas Engine 9 

shaft, so that it makes two revolutions for one of the other. The 
pumps therefore make one up-and-down stroke for each up or 
down stroke of the motor piston ; the angles of the cranks are so 
set that they (pumps) discharge their contents into one or other side 
of the motor cylinder at every stroke ; the exhaust gases are partly 




Fig. 5.— Barnett Engine. 

displaced by the fresh explosive mixture, and the motor piston com- 
pletes the compression in the motor cylinder itself. When full up 
or down the igniting cock acts, and the explosion drives the piston 
to the middle of its stroke ; it here runs over a port in the middle 
of the cylinder, and the pressure at once falls to atmosphere. 



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io The Gas Engine 

a is the motor piston ; b is the air-pump piston ; c is the gas- 
pump piston, which is behind the air-pump, and therefore not 
seen in the section ; d is the main crank shaft ; e the pump shaft 
driven from the main shaft by the wheels f and g. The engine 
is exceedingly interesting as the first in which the compression is 
accomplished in the motor cylinder, but it is not so good a machine 
as the first because of the difficulty of obtaining a sufficient amount 
of expansion. 

From 1838 to 1854 inclusive eleven British patents were applied 
for ; some were not completed but only reached the provisional 
stage. Of these patents by far the most important is Barnett's ; the 
others are interesting as showing the gradual increase of attention 
the subject attracted. The other names are Ador, 1838 ; Johnson, 
1 84 1 ; Robinson, 1843 ; Reynolds, 1844 ; Brown, 1846 ; Roger, 
1853, also Bolton and Webb, making three patents for the year ; 
for 1854 two patents, Edington and Barsanti and Matteucci. None 
of the proposals in these patents are really valuable or novel, 
being anticipated by either Street, Wright, or Samuel Brown. 
Robinson's is the best, being similar to Lenoir's in some of its 
details, and showing distinctly a better understanding of gas 
engine detail. 

A. K Newton y 1855, No. 562. — This specification is interesting, 
and describes for the first time a form of igniting arrangement 
only now coming into use ; it seems to be identical with the 
invention of the American Drake, although not described as a 
communication from him. It is a double-acting engine, and takes 
into the cylinder a charge of gas and air mixed, during a portion 
of the stroke, at atmospheric pressure. The igniting arrangement 
is a thimble-shaped piece of hard cast-iron which projects into a 
recess formed in the side of the cylinder ; it is hollow, and is kept 
at all times red-hot by a blow-pipe flame projected into it by a small 
pump. When the piston uncovers the recess the explosive gases 
coming in contact with it ignite, and the pressure produced drives 
it forward. 

This is the first instance of ignition by contact with red-hot 
metal ; the proposal has often been made since then in varying 
forms. 

Barsanti and Matteucci, 1857, No. 1655. — This is the first free 



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Historical Sketch of the Gas Engine 1 1 

piston engine ever proposed ; instead of allowing the explosion to act 
directly upon the motive power shaft through a connecting rod, 
at the moment of explosion the piston is perfectly free. The 
cylinder is very, long, and is placed vertically. When the explosion 
occurs, it expends its power in giving the piston velocity ; the 
expansion therefore takes place with considerable rapidity, and 
the piston, gaining speed until the pressure upon it falls to atmo- 
sphere, moves on, till the energy of motion is absorbed doing work 
on the external air, lifting the piston and in friction. When the 
energy is all absorbed in this manner it stops ; it has reached the 
top of its stroke. A partial vacuum has been formed in the cylinder, 
and the weight has been raised through the stroke. It now 
returns under the pressure of the atmosphere and its own weight ; 
in returning, a rack attached to the piston engages the motive shaft 
and drives it. The cooling of the gases as the piston descends 
continues and helps to keep up the vacuum. 

The method although indirect is economical. Three advantages 
are gained by it — rapid expansion, considerable expansion (an ex- 
pansion of six times is common in these engines), and also some 
of the advantages of a condensor. 

Fig. 6 shows a vertical section of their best modification. The 
motor piston a working in the tall vertical cylinder b is attached to 
the rack c, which works into the toothed wheel d. The motor 
shaft e revolves in the direction of the arrow, and it is provided 
with a ratchet ; a pall upon the wheel d engages the ratchet on the 
down stroke of the piston only, on the up stroke it slips freely 
past the ratchet. The piston a is therefore quite free to move 
without the shaft on the up stroke, but it engages on the down 
stroke. The cams f and g are arranged to strike projections 
upon the rack, and so raise or lower the piston. It is raised when 
the charge is to be taken in, and lowered when it has completed 
its working stroke and the exhaust gases have to be discharged. 
When raised the valve h is in the position shown. Air first enters 
the cylinder through the port i, which also serves to discharge the 
exhaust. After the piston has uncovered the port k the valve h 
shuts on i, opening at the same time on k ; the gas supply then 
enters and mixes more or less perfectly with the air previously 
introduced. 



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12 



The Gas Engine 



A small further movement of the piston now closes the valve, 
and the explosion is caused by the passage of the electric spark in 
the position indicated upon the drawing. The piston shoots up 




Fig. 6. — Barsanti and Matteucci Engine, 1857. 

freely to the top of its stroke, to give out the work stored up usefully 
upon its return. 

As the next engine to be described marks the beginning of the 



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Historical Sketch of the Gas Engine 13 

practicable stage of gas engine development, it is advisable to 
summarise before proceeding. 

Previous to i860 the gas engine was entirely in the experimental 
stage. Many attempts were made, but none of the inventors 
sufficiently overcame the practical difficulties to make any of their 
engines commercially successful. This was mostly due to the 
very serious nature of the difficulties themselves, but it was also 
due to too great ambition of the inventors ; they wished not only 
to compete with the steam engine for small powers, but for large 
powers. They thought in fact more to displace the steam engine 
than to compete with it. 

This is clearly shown in many of their descriptions of the appli- 
cations of their inventions. 

The greatest credit is due to Wright and Barnett. Wright 
very closely proposed the modern non-compression system, Barnett 
the modern compression system. Barnett is also the originator of 
one of the modern flame systems for ignition. Barsanti and 
Matteucci follow in order of merit as the inventors of the free-piston 
gas engine. 

M. Lenoir occupies the honourable position of the inventor 
of the first gas engine ever actually introduced to public use. The 
engine was not strikingly novel ; nothing was done in it which had 
not been proposed before, but its details were thoroughly and 
carefully worked out. It was in fact the first to emerge from the 
purely experimental stage. Lenoir's real credit consists in over- 
coming the practical difficulties sufficiently to make previous 
proposals fairly workable. 

The principle is exceedingly simple and evident The piston 
moves forward for a portion of its-stroke, by the energy stored in 
the fly wheel, and takes into the cylinder a charge of gas and air 
at the ordinary atmospheric pressure. The valves cut off com- 
munication, and the explosion is occasioned by the electric spark ; 
this propels the piston to the end of the stroke. Exhausting is 
done precisely as in the steam engine. 

The engine is simply an ordinary high-pressure steam engine with 
valves arranged to admit gas and air and discharge the products 
of combustion. Fig. 7 is an external elevation of a three-horse 
engine. It was first constructed in Paris in i860 by M. Hippolyte 



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14 



The Gas Engine 




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Historical Sketch of the Gas Engine 1 5 

Marinonl In Moigno's 'Cosmos' of that year it is stated that two 
engines were in course of manufacture, one of six horse-power, the 
other of twenty. 

The early statements of its economy were ludicrously inaccurate. 
A one horse-power engine consumed, it was said, but 3 cubic metres 
(106 cubic ft. nearly) of coal gas in twelve hours' work, and therefore 
cost for fuel not more than one-half of what a steam engine would 
have done. 

The actual consumption was speedily shown to be much nearer 
3 cubic metres per effective horse-power per hour. 

Notwithstanding the high consumption, the engine had many 
good points ; its action was exceedingly smooth ; no shock whatever 
was heard from the explosion. Indeed it is quite impossible when 
watching the engine in motion to realise that regular explosions 
are occurring. The motion is as smooth and silent as in the best 
steam engines. 

In the * Practical Mechanics' Journal ' of August 1865, there 
is an article describing the progress made by the engine since the 
date of its introduction, from which it appears that in Paris and 
France from 300 to 400 engines were then at work, the power ranging 
from half horse to three horse. 

The Reading Iron Works Company, Limited, at Reading, un- 
dertook the manufacture for this country. One hundred engines 
were made and delivered by them ; several of them have continued 
at work till now. Notably one engine inspected by the author at 
Petworth House, Petworth, worked for twenty years pumping water, 
and is even yet in good condition. 

The work performed by the engines was multifarious in its 
character — printing, pumping water, driving lathes, cutting chaff, 
sawing stone, polishing marble, in fact, wherever from one-half to 
three horse-power was sufficient. 

Lenoir's patent in this country was obtained by J. H. Johnson, 
i860, No. 335. It describes very closely the engine as manu- 
factured both in France and England. The subsequent patent, 
1 86 1, No. 107, does not seem to have been carried into effect. 

These specifications contain many erroneous ideas, showing 
the notions then prevalent among inventors of the nature of 
gaseous explosions. Lenoir erroneously supposed that the economy 



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1 6 The Gas Engine 

of his engine would be improved if he could obtain a slower 
explosion. He evidently thought that the power imparted to the 
piston by explosion was similar in nature to a sudden blow — a 
rapid rise of pressure, and a fall nearly as rapid. He therefore 
attempted to avoid explosion by such expedients as stratification 
and injection of steam or water spray. The stratification idea he 
very clearly expressed in his second specification, stating that i the 
object of preventing the admixture of air and gas is to avoid 
explosion.' It is somewhat extraordinary to find notions so 
erroneous common at a time when Bunsen's work had clearly 
proved the continuous nature of the combustion in gaseous explo- 
sions, and when Him had made experiments which showed that 
the heat evolved by explosion in a gas engine was only a small 
part of the total heat of the combustion, the heat which did not 
appear during explosion being produced during expansion. 

Other speculations on the cause of the uneconomical working 
of the engine were frequent, but the true reason was fully explained 
by Gustav Schmidt in a paper read before ' The Society of Ger- 
man Engineers' in 1861. He states : 'The results would be far 
more favourable if compression pumps, worked from the engine, 
compressed the cold air and cold gas to three atmospheres before 
entrance into the cylinder ; by this a greater expansion and trans- 
formation of heat is possible.' 

This opinion became common at this time. Compression 
engines were proposed with great clearness and a full understand- 
ing of the advantages to be gained. 

Million, 186 1, No. 1840/ — This Frenchman had exceedingly 
clear ideas of the advantages of compression ; he evidently con- 
siders himself as the first to propose its use in a gas engine, 
apparently unaware of the existence of Barnett's engine already 
described. He claims the exclusive right to use compression in 
the most emphatic language. 

The first engine described is exactly what Schmidt asks for. 
Separate pumps compress the air and gas into a reservoir, from 
which the movement of the motor piston, during a portion of the 
stroke, withdraws its charge under compression. Ignition is ac- 
complished by the electric spark, and the piston moves forward 
under the high pressure produced. He states : 



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Historical Sketch oft/ie Gas Engine 17 

• In ordinary air engines the operation of the motive cylinders 
is analogous to that of the pumps, the result being that there are 
two cylinders, which act in directions contrary to each other, and 
that the pump, which is an organ of resistance, even works at a 
greater pressure than that of the motive cylinder, which is an 
organ of power. Thus these engines are very large in proportion to 
their power. On the contrary by employing gases under the con- 
ditions above explained, these engines will exert great power in 
proportion to their dimensions. The sudden ignition of the gases 
in the motive cylinder causes the latter to work at an operative 
pressure much greater than that of the pumps.' 

The advantage of compression in a gas engine could not be 
more fully and clearly stated But he goes even a step further ; 
he sees that the portion of the motor piston stroke spent in taking 
in the charge under compression, is a disadvantage, and he pro- 
poses to make the whole stroke available for power by providing a 
space at the end of the cylinder in which the gases are compressed. 

'Instead of introducing the cold gases into the cylinders, 
during a portion of the stroke and igniting them afterwards, when 
the induction ceases . . . another arrangement might be adopted. 
The motive cylinder might be made longer than necessary, in 
order that the piston should always leave between it and the end 
of the cylinder a greater or less space, according to the pleasure 
of the constructor, such as one-fourth or one-third, more or less, 
of the volume generated by the motive piston. This space is 
called by the inventor a cartridge. On opening the slide valve 
the gases could be allowed to enter suddenly from the pressure 
reservoir into this cartridge towards the dead point, and this induc- 
tion having ceased, an electric spark would ignite the gases in 
the cartridge by which the driving piston would be set in motion. ' 

Such an engine would resemble in its action the best modern 
compression engines. The difficulties of ignition however are too 
considerable to be overcome without further detail. 

The compression idea at this date was evidently widely 
spread, because it again crops up in a remarkably clever pamphlet 
by M. Alph. Beau de Rochas, published at Paris in 1862. He 
advances a step further than Million, and investigates the con- 
ditions of greatest economy in gas engines using compression, 

c 



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1 8 The Gas Engine 

with reference to volume of hot gases and surfaces exposed. He 
states that to obtain economy with an explosion engine, four con- 
ditions are requisite : 

i. The greatest possible cylinder volume with the least pos- 
sible cooling surface. 

2. The greatest possible rapidity of expansion. 

3. The greatest possible expansion ; and 

4. The greatest possible pressure at the commencement of the 
expansion. 

In using boiler tubes, he states, the efficiency of the heat 
transmitted increases with reduction in the diameter of the tubes. 
In the case of engine cylinders, therefore, the loss of heat of explo- 
sion would be in inverse ratio to the diameter of the cylinders. 

Therefore, he reasons, an arrangement which for a given con- 
sumption of gas, gives cylinders of the greatest diameters, will 
give the best economy, or least loss of heat to the cylinder. One 
cylinder only must be employed in such an engine. 

But loss of heat depends also upon time ; cooling, therefore, 
will be proportionately greater as the working speed is slower. 

The sole arrangement capable of combining these conditions, he 
states, consists in using the largest possible cylinder, and reducing 
the resistance of the gases to a minimum. This leads, he states, 
to the following series of operations. 

1. Suction during an entire outstroke of the piston. 

2. Compression during the following instroke. 

3. Ignition at the dead point and expansion during the third 
stroke. 

4. Forcing out of the burned gases from the cylinder on the 
fourth and last return stroke. 

The ignition he proposes to accomplish by the increase of 
temperature due to compression. This he expects to do by 
compressing to one- fourth of the original volume. 

In our own country the late Sir C. W. Siemens proposed com- 
pression in 1862. The idea was exceedingly widely spread, as is 
evident from those numerous and independent inventions. The 
practical experience to enable it to be successfully effected had 
yet to be created, however, and this took many years of patient 
work. 



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Historical Sketch of the Gas Engine 



19 



The igniting arrangement was the first weak point requiring 
improvement. The electrical method of Lenoir was exceedingly 
delicate and troublesome. 




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20 Tfie Gas Engine 

Hugon's engine, produced in 1865, was similar to Lenoir's ; 
but the igniting was accomplished by flame, a modification of 
Barnett's, 1838, using a slide valve instead of a lighting cock. 
The flame ignition was certain and easily kept in order. In 
other points the engine was a great improvement upon its prede- 
cessor. The lubrication was improved by injecting water into the 
cylinder and the cooling water jacket was better arranged. As a 
result the consumption of gas was reduced. 

Fig. 8 is an external elevation of the Hugon engine. 

Mr. Otto now appears upon the scene. Before him much had 
been done in inventing and studying engines, but it remained for 
him by sheer perseverance and determination of character, to 
overcome all difficulties and reduce to successful practice the 
theories of his predecessors. 

In 1867 Messrs. Otto and Langen exhibited at the Paris exhibi- 
tion of that year, their free piston engine, exterior elevation shown 
at fig. 9. It was absolutely identical in principle with the previous 
invention of Barsanti and Matteucci, but the details were com- 
pletely and successfully carried out The Germans succeeded 
commercially and scientifically when the Italians completely 
failed 

Flame ignition was used and great economy was obtained, a half- 
horse engine, according to Professor Tresca, giving over half-horse 
power effective, on a gas consumption at the rate of 44 cubic feet 
per effective horse-power per hour. This is less than half the 
consumption of Lenoir or Hugon ; accordingly the prejudice ex- 
cited by the strange appearance and noisy action of the engine 
did not prevent its sale in large numbers. It completely crushed 
Lenoir and Hugon, and held almost sole command of the market 
for ten years, several thousands being constructed in that period. 

The Brayton gas engine appeared in America in 1873, but 
although more mechanical than any free piston engine, its economy 
was insufficient to enable it to compete. It was better than Lenoir 
or Hugon, but not nearly so good as Otto and I^angen. 

Other inventors attempted free piston engines, but with small 
success. 

In 1876 Mr. Otto superseded his former invention by the 
production of the ' Otto Silent ' engine, now known all over the 



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Historical Sketch of the Gas Engine 



21 



globe. It is a compression engine, using the precise cycle described 
in 1862 by Beau de Rochas, but carried out in a most perfect 
manner and using a good form of flame ignition, a modified Otto and 
Langen valve in fact The economy is greater than that of any 




Fig. 9.— Otto and Langen Free Piston Engine. 

previous engine, one indicated horse being obtained upon 20 cubic 
feet of gas, or one effective horse upon 24 to 30 cubic feet pet 
hour. 

This engine has established gas engines upon a firm commercial 
basis, 15,000 having been sold since its invention ; this represents 
at least an effective power of 90,000 horses. 



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22 Tlie Gas Engine 

Strangely enough, although Mr. Otto is the greatest and most 
successful gas engine inventor who has yet appeared, he adheres 
to Lenoir's erroneous ideas, and in his specification 2081 of 1876 
he attributes the economy of his machine to a slow explosion caused 
by arrangement of gases within the cylinder. 

The compression, which is the real cause of the economy and 
efficiency of the machine, he seems to consider as an accidental and 
unessential feature of his invention. 

The gas engine, like all great inventions, is the result of the 
long-continued labour of many minds ; it is a gradual growth due 
to the united labours of many inventors. In the earlier days of 
motive power, explosion was as much in the minds of the inventors, 
Huyghens and Papin, as steam, but the mechanical difficulties 
proved too great. The constructive skill of the time was heavily 
taxed by the rude steam engine of Newcomen, and still more 
unequal to the invention of James Watt ; it was in 1774 that Watt 
ran his first successful steam engine at Soho Works, Birmingham. 
Twenty years later, 1794, Street's gas engine patent indicated the 
direction of men's minds, seeking a rival for steam before steam had 
been completely introduced. The experience and skill accumulating 
in the construction of the steam engine made the gas engine more 
and more possible. 

The proposals of Brown, 1823 ; Wright, 1833 ; Barnett, 1838 ; 
Barsanti and Matteucci, 1857, show gradually increasing knowledge 
of detail and the difficulties to be overcome, all leading to the first 
practicable engine in i860, the Lenoir. 

Since that date till now, twenty-five years, great advances have 
been made, and at present the gas engine is the only real rival to 
steam. 



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23 



CHAPTER I. 

THE GAS ENGINE METHOD. 

Gas engines, while differing widely in theory of action and 
mechanical construction, possess one feature in common which 
distinguishes them from other heat engines : that feature is the 
method of heating the working fluid. 

The working fluid is atmospheric air, and the fuel required to 
heat it is inflammable gas. In all gas engines yet produced, the 
air and gas are mixed intimately with each other before introduc- 
tion to the motive cylinder ; that is, the working fluid and the 
fuel to supply it with heat are mixed with each other before the 
combustion of the fuel. 

The fuel, which, in the steam and in most hot-air engines, is 
burned in a separate furnace, is, in the gas engine, introduced 
directly to the motive cylinder and burned there. It is indeed 
part of the working fluid. 

This method of heating may be called the gas-engine method, 
and from it arises at once the great advantages and also the great 
difficulties of these motors. 

Compare first with the steam engine. In it there exist two 
great causes of loss : water is converted into steam, absorbing a 
great amount of heat in passing from the liquid to the gaseous 
state ; after it has been used in the engine it is rejected into the 
atmosphere or the condenser, still existing as steam. The heat 
necessary to convert it from the liquid to the gas is consequently 
in most part rejected with it. Loss, occurring in this way, would 
be small if high temperatures could be used ; but this is the point 
where steam fails. High temperatures cannot be obtained without 
pressure so great as to be quite unmanageable. The attempt to obtain 
high temperatures by super-heating has often been made, but with- 



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24 The Gas Engine 

out any substantial success. Although the difficulty of excessive 
pressure is avoided, another set of troubles are introduced. All the 
heat to be given to the gaseous steam must pass through the iron 
plates forming the boiler or super-heater, which plates will only 
stand a comparatively low temperature, certainly not exceed- 
ing that of a low red heat, or about 6oo° to 700 C. Steam, 
being a gas, is much more difficult to heat than water ; it follows 
that even these temperatures cannot be attained without enormous 
addition to the heating surface. The difficulties of making a 
workable engine using high temperature steam are so great that 
even so distinguished an engineer and physicist as the late Sir 
C. W. Siemens failed in his attempts, which extended over many 
years. It may be taken then that low temperature is the natural 
and unavoidable accompaniment of the steam method, arising 
from the necessary change of the physical state of the working 
fluid, and the limited temperature which iron will safely bear. 
The originators of the science of thermodynamics have long 
taught that the maximum efficiency of a heat engine is obtained 
when there is the maximum difference between the highest and 
lowest temperatures of the working fluid. So long ago as 1854, 
Professor Rankine read a paper before the British Association, 
' On the means of realising the advantages of the Air Engine,' in 
which he expresses his belief that such engines will be found to be 
the most economical means of developing motive power by the 
agency of heat. In this opinion he stood by no means alone. 
Engineers so able as Stirling, Ericsson, and Siemens ; physicists 
so distinguished as Dr. Joule, and Sir Wm. Thomson, devoted 
much energy and study to their practice and theory. Notwith- 
standing all their efforts, aided by a host of less able inventors, 
the difficulties proved too formidable ; and although more than 
thirty years have now passed since Rankine announced his belief, 
the hot-air engine proper, has made no real advance. Similar 
causes to those acting in the steam engine impose a limit here. 
It is true the complication of changing physical state is avoided, 
but the limited resistance of iron to heat acts as powerfully 
as ever. Air is much more difficult to heat than water, and, there- 
fore, requires a much larger surface per unit of heat absorbed 
In the larger hot-air engines, accordingly, the furnaces and heating 



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The Gas Engine Method 25 

surfaces gave great trouble. Very low maximum temperatures 
were attained in practice. In a Stirling engine giving out thirty- 
seven brake horse-power, the maximum temperature was only 
343 C. j in the engines of the ship ' Ericsson/ the maximum was 
only about 212 C, according to Rankine, the indicated power 
being about 300 horses. These figures show that the heating 
surfaces were insufficient, as in both cases the furnaces were pushed 
to heat the metal to a good red. A method of internal firing was 
proposed, first by Sir George Cayley and afterwards carried out 
with some success by others ; the furnace was contained in a 
completely closed vessel, and the air to be heated was forced 
through it before passing to the motor cylinder. The plan gave 
better results, but the temperature of 700 C. was still the limit, as 
the strength of the iron reservoir had to be considered, and the 
hot gases had to pass through valves. Wenham's engine, described 
in a paper read before the Institution of Mechanical Engineers in 
1873, is a good example of this class. In it the highest temperature 
of the working fluid, as measured by a pyrometer, was 608 C. ; 
higher temperatures could easily have been got but the safety of 
the engine did not permit it. Professor Rankine in his work on 
the steam engine has very fully discussed the disadvantages arising 
from low maximum temperatures. He calculates that in a perfect 
air engine without regenerator an average pressure of 8-3 lbs. 
per square inch would only be attained with a maximum of 
2 16 "6 lbs. per square inch, thus necessitating great strength of 
cylinder and working parts for a very small return in effective 
power. In the ' Ericsson,' the average effective pressure was less 
than this, being only about 2 lbs. per square inch ; it had four air 
cylinders each of 14 feet diameter, and only indicated 300 horse- 
power. Stirling's motor cylinder did not give a true idea of the 
bulk of the engine, as the real air-displacer was separate. Even 
with Wenham's machine the bulk was excessive, an engine of 
24 inches diameter cylinder and 1 2 inches stroke giving 4 horse- 
power. 

Those facts sufficiently illustrate the practical difficulties which 
prevented the development of the hot-air engine proper. All flow 
from the method of heating. Low temperature is necessary to 
secure durability of the iron. 



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26 T/ie Gas Engine 

All hot-air engines are, therefore, very large and very heavy 
for the power they are capable of exerting. 

The friction of the parts is so great that although the theoreti- 
cal efficiency of the working fluid is higher than in the best steam 
engines, the practical efficiency or result per horse available for 
external work is not nearly so great The best result ever claimed 
for Stirling's engine is 27 lbs. of coal per bk. horse-power per 
hour, probably under the truth, but even allowing it, a first class 
steam engine of to-day will do much better. According to Prof. 
Norton, the engines of the ' Ericsson ' used 1*87 lbs. of anthracite 
per indicated horse-power per hour ; but the friction must have been 
enormous. Compared with the steam engine, the practical disadvan- 
tages of the hot-air engine are much greater than its advantage of 
theory. Owing to the great inferiority of air to boiling water as a 
medium for the convection of heat, the efficiency of the furnace is 
much lower ; owing to the high maximum and low available pres- 
sure, the friction is much greater— which disadvantages in practice 
more than extinguish the higher theoretical efficiency. 

The gas engine method of heating by combustion or explosion 
at once disposes of those troubles ; it not only widens the limits 
of the temperatures at command almost indefinitely, but the causes 
of failure with the old method become the very causes of success 
with the new method. 

The difficulty of heating even the greatest masses of air is 
quite abolished. The rapidly moving flash of chemical action 
makes it easy to heat any mass, however great, in a minute fraction 
of a second ; when once heated the comparatively gradual con- 
vection makes the cooling a very slow matter. The conductivity 
of air for heat is but slight, and both losing and receiving heat 
from enclosing walls are carried on by the process of convection, 
the larger the mass of air the smaller the cooling surface relatively. 
Therefore the larger the volumes of air used, the more economical 
the new method, the more difficult the old. The low conductivity 
for heat, the cause of great trouble in hot-air machines, becomes 
the unexpected cause of economy in gas engines. If air were a 
rapid carrier of heat, cold cylinder gas engines would be impos- 
sible. The loss to the sides of the enclosing cylinders would be 
so great that but little useful effect could be obtained. Even as 



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The Gas Engine Met/tod 27 

it is, present loss from this cause is sufficiently heavy. In the 
earlier engines as much as three-fourths of the whole heat of the 
combustion was lost in this way ; in the best modern engines so 
much as one-half is still lost. 

A little consideration of what is occurring in the gas engine 
cylinder at each explosion will show that this is not surprising. 
Platinum, the most infusible of metals, melts at about 1700 C; 
the ordinary temperature of cast iron flowing from a cupola is 
about 1200 C; a temperature very usual in a gas engine cylinder 
is 1600 C, a dazzling white-heat. The whole of the gases filling 
the cylinder are at this high temperature. If one could see the 
interior it would appear to be filled with a blinding glare of light 
This experiment the writer has tried by means of a small aperture 
covered with a heavy glass plate, carefully protected from the 
heat of the explosion by a long cold tube. On looking through 
this window while the engine is at work, a continuous glare of 
white light is observed. A look into the interior of a boiler 
furnace gives a good notion of the flame filling the cylinder of 
a gas engine. 

At first sight it seems strange that such temperature can be 
used with impunity in a working cylinder ; here the convenience 
of the method becomes evident. The heating being quite inde- 
pendent of the temperature of the walls of the cylinder, by the use 
of a water-jacket they can be kept at any desired temperature. 
The same property of rapid convection of heat, so useful for 
generating steam from water, is essential in the gas engine to keep 
the rubbing surfaces at a reasonable working temperature. In 
this there is no difficulty, and notwithstanding the high tempera- 
ture of the gases, the metal itself never exceeds the boiling point 
of water. 

So good a result cannot of course be obtained without careful 
proportioning of the cooling surfaces for the amount of heat to be 
carried away ; in all modern engines this is carefully attended to, 
with the gratifying result that the cylinders take and retain a 
polished surface for years of work just as in a good steam engine. 

The gas engine method gives the advantage of higher tempera- 
ture of working fluid than is attainable in any other heat engine, 
at the same time the working cylinder metal may be kept as cool 



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28 The Gas Engine 

as in the steam engine. It also allows of any desired rate of heat- 
ing the working fluid in any required volumes. 

In consequence of high temperatures the available pressures 
are high, and therefore the bulk of the engine is small for the 
power obtained. 

It realises all the thermodynamic advantages claimed for the 
hot-air engine without sacrificing the high available pressures and 
rapid rate of the generation of power which is the characteristic of 
the steam engine. 

For rapid convection of heat existing in the steam boiler is 
substituted the still more rapid heating by explosion or combustion, 
a rapidity so superior that the power is generated for each stroke 
separately as required, there being no necessity to collect a great 
magazine of energy. 

The only item to the debtor side of the gas engine account 
is the flow of heat through the cylinder walls, which disadvantage 
is far more than paid for by the advantages. 



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29 



CHAPTER II. 

GAS ENGINES CLASSIFIED. 

Although the gas engine patents now in existence number many 
hundreds, the essential differences between the inventions are not 
great. In their working process they may be divided into a few 
well-defined types : 

i. Engines igniting at constant volume, but without previous 
compression. 

2. Engines igniting at constant pressure, with previous com- 
pression. 

3. Engines igniting at constant volume, with previous com- 
pression. 

The first type is the simplest in idea ; it is the most apparent 
method of obtaining power from an explosion. 

In it the engine draws into its cylinder gas and air at atmos- 
pheric pressure, for a part of its stroke, in proportions suitable for 
explosion ; then a valve closes the cylinder, and the mixture is 
ignited. The pressure produced pushes forward the piston for 
the remainder of its travel, and upon the return, stroke the pro** 
ducts of the combustion are expelled exactly as the exhaust of a 
steam engine. By repeating the same process on the other side 
of the piston, a kind of double-acting engine is obtained. It is 
not truly double-acting, as the motive impulse is not applied 
during the whole stroke, but only during that portion of it left 
free after performing the necessary function of charging with the 
explosive mixture. 

The working cycle of the engine consists of four operations : 

1. Charging the cylinder with explosive mixture. 

2. Exploding the charge. 

3. Expanding after explosion. 

4. Expelling the burned gases. 



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30 TJie Gas Engine 

To carry it out in a perfect manner, the mechanism must be 
so arranged that during the charging, the pressure of the gases in 
the cylinder does not fall below atmosphere ; there must be no 
throttling of the entering gases. The cut- off and the explosion 
must be absolutely simultaneous and also instantaneous, so that 
the heat may be applied without change of volume, and thereby 
produce the highest pressure which the mixture used is capable 
of giving. The expansion will be carried far enough to reduce 
the pressure of the explosion to atmosphere ; and the exhaust 
stroke will be accomplished without back pressure. The charge 
in entering must not be heated by the walls of the cylinder, but 
should remain at the temperature of the atmosphere till the very 
moment previous to ignition. At the same time, the cylinder 
should not cool trie gases after the explosion, no heat should dis- 
appear except through expansion doing work. 

Although all these conditions are necessary to the perfect 
cycle, it is evident that no actual engine is capable of combining 
them. Some throttling at the admission of the mixture, and a 
little back pressure during the exhausting are unavoidable ; some 
time must elapse between the closing of the inlet valve and the 
explosion, in addition to the time taken by the explosion itself. 
Heat will be communicated to the entering gases and lost by the 
exploded gases to the walls of the cylinder. 

The actual diagram taken from an engine will therefore differ 
considerably from the theoretic one. 

The theoretical conditions are to a great extent contradictory. 

The idea of the type, however, is easily comprehensible, and 
evidently suggested by the common knowledge of the destructive 
effect of accidental coal gas explosions which occurred soon after 
the introduction of gas into general use. 'The power is there, let 
us use it like steam in the cylinder of a steam engine,' said the 
early inventors. 

The two most successful engines of this type were Lenoir's 
and, later, Hugon's, for very small powers ranging from one man 
to half-horse. Simple forms of this type are still in extensive use. 
The most widely known of these is the Bisschof, a French inven- 
tion. 

The second type is not so simple in its main idea, and required 



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Gas Engines Classified 3 1 

much greater knowledge of detail, both mechanical and theoretical. 
As a hot-air engine its theory was originally proposed by Sir Geo. 
Cayley, and, later, by Dr. Joule and Sir Wm. Thomson. As a 
hot-air engine it failed for the reasons discussed in the previous 
chapter. 

In it the engine is provided with two cylinders of unequal 
capacity ; the smaller serves as a pump for receiving the charge 
and compressing it, the larger is the motor cylinder, in which the 
charge is expanded during ignition and subsequent to it. 

The pump piston, in moving forward, takes in the charge at 
atmospheric pressure, in returning compresses it into an inter- 
mediate receiver, from which it passes into the motor cylinder in 
a compressed state. A contrivance similar to the wire gauze in a 
Davy lamp commands the passage between the receiver and the 
cylinder, and permits the mixture to be ignited on the cylinder 
side as it flows in without the flame passing back into the 
receiver. 

The motor cylinder thus receives its working fluid in the state 
of flame, at a pressure equal to, but never greater than, the 
pressure of compression. At the proper time, the valve between 
the motor and the receiver is shut, and the piston expands the 
ignited gases till it reaches the end of its stroke, when the exhaust 
valve is opened, and the return expels the burned gases. 

The ignition here does not increase the pressure, but increases 
the volume. The pump, say, puts one volume or cubic foot into 
the receiver ; the flame causes it to expand while entering the 
cylinder to two cubic feet. It does the work of two cubic feet in 
the motor cylinder, so that, though there is no increase of pres- 
sure, there is nevertheless an excess of power over that spent in 
compressing. 

In the first type of engine the heat is given to the working 
fluid at constant volume, in the second type the heat is given to 
the working fluid at constant pressure during change of volume. 

The working cycle of the engine consists of five operations : 

1. Charging the pump cylinder with gas and air mixture. 

2. Compressing the charge into an intermediate receiver. 

3. Admitting the charge to the motor cylinder in the state of 
flame, at the pressure of compression. 



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32 T/te Gas Engine 

4. Expanding after admission. 

5. Expelling the burned gases. 

To carry out the process perfectly the following conditions 
would be required. 

No throttling during admission of the charge to the pump. 

No heating of the charge as it enters the pump from the 
atmosphere. 

No loss of the heat of compression to the pump and receiver 
walls. 

No throttling as the charge enters the motor cylinder from the 
receiver. 

No loss of heat by the flame to the sides of the motor cylinder 
and piston. 

And last, No back pressure during the exhaust stroke. 

The exhaust gases also must be completely expelled by the 
motor piston ; that is, the motor cylinder should have no clear- 
ance. 

The requirements of this type, although sufficiently numerous 
and exacting, are not so contradictory among themselves as in the 
first. 

Although every engine of the kind yet made fails to fulfil them, 
it is quite possible that a machine very closely approximating may 
be yet constructed. 

The most successful engines of this kind have been Brayton's 
and Simon's, the first an American invention, and the second 
an English adaptation of it Sir C. W. Siemens proposed such 
an engine in 1861, but does not seem to have been successful in 
carrying it out. In i860 it was also proposed by F. Million, but 
without a sufficient understanding of the mechanical detail neces- 
sary for a working machine. 

Brayton's engine was made in considerable numbers in America, 
and was applied by him to drive a good-sized launch, petroleum 
being used as the fuel instead of gas. It was exhibited at the Cen- 
tennial Exhibition in Philadelphia ; at the Paris exhibition of 1878 
by Simon. 

The third type is the best kind of compression engine yet 
introduced ; by far the largest number of gas engines in every day 
use throughout the world are made in accordance with its require- 



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Gas Engines Classified 33 

ments. In theory it is more easily understood as requiring two 
cylinders, compression and power. 

The leading idea, compression and ignition at constant volume, 
was first proposed by Barnett in 1838, then by Schmidt in more 
general terms, very fully by Beau de Rochas in i860 and also by 
F. Million in the same year. Otto, however, was the first to suc- 
cessfully apply it, which he did in 1876. 

The compression cylinder may be supposed to take in the 
charge of gas and air at atmospheric temperature and pressure ; 
compress it into a receiver from which the motor cylinder is sup- 
plied ; the motor piston to take in its charge from the reservoir in 
a compressed state ; and then communication to be cut off and 
the compressed charge ignited 

Here ignition is supposed to occur at constant volume, that is, 
the whole volume of mixture is first introduced and then fired ; 
the pressure therefore increases. The power is obtained by 
igniting while the volume remains stationary and the pressure in- 
creases. 

Under the pressure so produced, the piston completes its 
stroke, and upon the return stroke the products of the combus- 
tion are expelled 

In this case the working cycle of the engine consists of six 
operations : 

1. Charging the pump cylinder with gas and air mixture. 

2. Compressing the charge into an intermediate receiver. 

3. Admitting the charge to the motor cylinder under com- 
pression. 

4. Igniting the mixture after admission to the motor. 

5. Expanding the hot gases after ignition. 

6. Expelling the burned gases. 

To carry out the process perfectly, similar conditions are neces- 
sary to those in the second type. But the conditions are more 
contradictory. The gases entering the cylinder under pressure must 
not be heated by its walls ; no heat should be added till the igni- 
tion ; then, after ignition the gases must not lose heat to the 
cylinder— conditions which it is impossible for the same cylinder 
to fulfil simultaneously. 

In the engines constructed the receiver is dispensed with, for 

D 



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34 The Gas Engine 

reasons which will be explained in discussing the practical difficul- 
ties of construction ; but this does not in any way modify the 
theory, which shall first be discussed. 

The most considerably used engine of this kind is the Otto, 
next to it coming Clerk's engine, then Robson's by the Messrs. 
Tangye, and Andrews' Stockport compression engine. In none 
of these types does any part of the working cycle require either 
the heating or the cooling of the working fluid by the relatively 
slow processes of convection and conduction. 

Heating is accomplished by the rapid method of explosion or, 
if the term be preferred, combustion, and for the cooling neces- 
sary in all heat engines is substituted the complete rejection of 
the working fluid with the heat it contains and its replacement by 
a fresh portion taken from the atmosphere at the atmospheric 
temperature, which is the lower limit of the engines. 

This is the reason why those cycles can be repeated with 
almost indefinite rapidity, and why gas engines can be run at 
speeds equal to steam engines, while the old hot-air engines could 
not be run fast, because of the very slow rate at which air could be 
heated and cooled by contact. 

There still remains one important type of gas engine not 
included in this classification ; in it part of the efficiency is de- 
pendent on cooling by contact, and consequently only a slow rate 
of working stroke can be obtained. It is the kind of engine 
known as the free piston or atmospheric gas engine. It may be 
regarded as a modification of the first type. The first part of its 
action is precisely similar, the latter part differs considerably. 

It may be called Type One A. In it the piston moves for- 
ward, taking in its charge of gas and air from the atmosphere at 
the atmospheric pressure and temperature. When cut off it is 
ignited instantaneously, the volume being constant and the 
pressure increasing ; the piston is not connected directly to the 
motor shaft, but is free to move under the pressure of the explo- 
sion, like the ball in a cannon. It is shot forward in the cylinder 
(which is made purposely very long) ; the energy of the explosion 
gives the piston velocity ; it therefore continues to move con- 
siderably after the pressure has fallen by expansion to atmos- 
phere ; a partial vacuum forms under the piston till its whole 



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Gas Engines Classified 35 

energy of motion is absorbed in doing work upon the exterior 
air. It then stops, and the external pressure causes it to perform 
its instroke, during which a clutch arrangement yokes it to the 
motor shaft, giving the shaft an impulse. The explosion is made 
to give its equivalent in work upon the external air, in forming a 
vacuum in fact ; the vacuum is increased by the cooling of the 
hot gases during the return of the piston. The piston proceeds 
completely to the bottom of the cylinder, expelling the products 
of combustion. So far as the working fluid of the engine is con- 
cerned the cycle consists of five operations : 

1. Charging the cylinder with explosive mixture. 

2. Exploding the charge. 

3. Expanding after explosion. 

4. Compressing the burned gases after some cooling. 

5. Expelling the burned gases. 

To carry it out perfectly, in addition to the requirements of the 
first type, the expansion should be carried far enough to lower the 
temperature of the working fluid to the temperature of the atmos- 
phere, and the compression to atmospheric pressure again should 
be conducted at that temperature ; that is, the compression line 
should be an isothermal. 

This kind of engine was proposed first by Barsanti and Mat- 
teucci in 1854, by F. H. Wenham in 1864, and then by Otto and 
Langen in 1866. The last named inventors were successful in 
overcoming the practical difficulties, and many engines were 
made and sold by them. Their engine, although cumbrous and 
noisy, was a good and economical worker \ many are still in use. 
The next best known engine of the kind was Gillies's, of which a 
considerable number were constructed and sold. 



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36 The Gas Engine 



CHAPTER III. 

THERMODYNAMICS OF THE GAS ENGINE. 

Beginning with Professor Rankine, able writers have so fully 
treated the thermodynamics of the air engine that but little can 
be added to the knowledge of the subject now in existence. The 
gas engine method of heating, however, introduces limits of 
temperature so extended and cycles of action so different from 
those possible in the air engine proper, that something remains to 
be done in applying the existing data. So far as the author is 
aware, this has been previously attempted by three writers only — 
Prof. R. Schottler, Dr. A. Witz, and himself. 

Before proceeding with the special consideration of the sub- 
ject, it is advisable for the sake of completeness to state briefly 
the general laws. In doing so Rankine will be followed as closely 
as possible. 

Thermodynamics Defined. 

' It is a matter of ordinary observation that heat, by expanding 
bodies, is a source of mechanical energy, and conversely, that 
mechanical energy, being expended either in compressing bodies 
or in friction, is a source of heat. 

* The reduction of the laws according to which such phenomena 
take place to a physical theory or connected system of principles 
constitutes what is called the science of thermodynamics. ' 

First Law of Thermodynamics. 

Heat and mechanical energy are mutually convertible, and 
heat requires for its production, and produces by its disappear- 
ance, mechanical energy in the proportion of 1,390 footpounds 
for each centigrade heat unit, a heat unit being the amount of 



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Thermodynamics of the Gas Engine 37 

heat necessary to heat one pound weight of water through i° C. 
This is Joule's law, having been first determined by him in 1843. 
It holds with equal truth for other forms of energy, and is a 
general statement of the great truth, that in the universe, energy is 
as incapable of creation or destruction as matter. Energy may 
change its form indefinitely while passing from a higher to a 
lower level, but it can neither be created nor destroyed. The 
energy of outward and visible movement of matter may be 
arrested and caused to disappear as movement of the whole mass 
in one direction, but its equivalent reappears as internal move- 
ment or agitation of the particles or molecules composing the 
body. Energy assumes many forms, but the sum of all remains 
a constant quantity, incapable of change of quantity, but capable 
of disappearing in one form and reappearing in another. 

Second Law of Thermodynamics. 

Although heat and work are mutually convertible and in 
definite and invariable proportions, yet no conceivable heat 
engine is able to convert all the heat given to it into work. 

Apart altogether from practical limitations, a certain portion 
of the heat must be passed from the hot body to the cold body in 
order that the remainder may assume the form of mechanical 
energy. To get a continuous supply of mechanical energy from 
heat depends upon getting a continuous supply of hot and cold 
substances : it is by the alternate expansion and contraction of 
some substance, usually steam or air, that heat is converted into 
mechanical energy. 

Perfect heat engines are ideal conceptions of machines which 
are practically impossible, but whose operations are so arranged 
that, if possible, they would convert the greatest conceivable 
proportion of the heat given to them into mechanical work. 

Efficiency. — The efficiency of a heat engine is the ratio of the 
heat converted into mechanical work to the total amount of heat 
which enters the engine. 

In this work the word Efficiency^ when used without qualifica- 
tion, bears this meaning only. 

The efficiency of a perfect heat engine depends upon two 



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38 The Gas Engine 

things alone : these are, the temperature of the source of heat and 
the temperature of the source of cold (allowing the expression). 
The greater the difference between these temperatures the greater 
the efficiency. That is, the greater will be the proportion of the 
total heat converted into mechanical energy, and the smaller the 
proportion of the total heat which necessarily passes by conduction 
from the hot to the cold body. 

Properties of Gases. — Gases are the most suitable bodies for 
use in heat engines ; they are almost perfectly elastic, and they ex- 
pand largely under the influence of heat 

A gas is said to be perfect when it completely obeys two 
laws : 

i. Boyle's law. 
2. Charles's law. 

Boyle's Law. — Suppose unit volume of gas to be contained in 
a cylinder fitted with a piston which is perfectly tight at unit 
pressure. Suppose the temperature to be kept perfectly constant. 
Then, according to Boyle's law, however the volume may be 
changed by moving the piston, the pressure is always inversely 
proportional to volume, that is, if volume becomes two, pressure 
becomes one-half; volume becomes three, pressure becomes 
one-third. 

The product of pressure and volume is always constant. 

Denoting pressure by /, and volume by v, 

Boyle's law is, / v = constant. 

Charles's Law. — If a gas kept at constant volume is heated, 
the pressure increases. If a gas is kept behind a piston which 
moves without friction so that the pressure upon the gas is always 
constant, the heat applied will cause it to expand. 

One volume of gas at o° C, if heated through i° C. will expand 
^1^, and become i 7 |ij volume, if the pressure is constant. If the 
rolume is constant, then its pressure will increase by 7 | 3 , that is, 
its pressure will become 1^77 of the original. In the same way 
if cooled i° C. below o° C, it will contract or diminish in pressure 
by sis, its volume or pressure becoming |I£ of what it is at o° C 

For every degree of heat or cold above or below o° C. a perfect 
gas expands or contracts by ^ I 3 of its volume at o° C. 



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Thermodynamics of the Gas Engine 39 

From this it is evident that a perfect gas, if cooled to 273 C. 
below o° C. will have neither volume nor pressure. 

This originally gave rise to the conception .of absolute zero of 
temperature. The absolute temperature of a body is ordinary 
temperature Centigrade + 273, just as the absolute pressure of any 
gas is its pressure above atmosphere plus atmospheric pressure. The 
absolute temperature of a body is its temperature above Centigrade 
zero + 273. 

The pressure or volume of a gas is therefore directly propor- 
tional to its absolute temperature. 

If /= pressure for absolute temperature /, and p x pressure for 
t l temperature, also absolute, 

then £-£; 
or if v be the volume at absolute temperature / and v 1 at t\ 

then 51 " ?' 
The Second Law {quantitative). — If heat be supplied to a perfect 
heat engine at the absolute temperature t 1 , and the absolute tem- 
perature of the source of cold is t, then the efficiency of thai 
engine is, denoting it by e, 

ip) __ fp fp 

E= =— = 1 .. 

T 1 T 1 

It is unity minus the lower temperature divided by the upper 

T 

temperature. The efficiency is greater or less as the fraction — { 

is less or greater. This fraction may be diminished either by 
reducing t or by increasing t 1 . The lowest available temperature 
is not capable of great variation, being in our climate about 290 
absolute. It therefore follows that efficiency could only be in- 
creased by increasing t 1 . 

Suppose t=29o° absolute and t 1 =58o° absolute. 

Then E=i-|tJ=i-i= 0-5. 
Suppose t=29o°, and T 1 = i45o°, a temperature common in 
gas engines, then 



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40 



The Gas Engine 



The efficiency increases with increase of the maximum tempe- 
rature. The second law, in its quantitative form, is the statement 
of the efficiency of any perfect heat engine in terms of absolute 
temperatures of the source of heat and the source of cold. 

Thermal Lines. — If a volume of air is contained in a cylinder 
having a piston and fitted with an indicator, the piston, if moved 
to and fro, will alternately compress and expand the air, and the 
indicator pencil will trace a line or lines upon the card, which lines 
register the change of pressure and volume occurring in the cylinder. 
If the piston is perfectly free from leakage, and it be supposed that 
the temperature of the air is kept quite constant, then the line so 
traced is called an Isothermal line, and the pressure at any point 
when multiplied by the volume is a constant according to Boyle's 
law, 

pv = a constant. 

If, however, the piston is moved in very rapidly, the air will not 
remain at constant temperature, but the temperature will increase 
because work has been done upon the air, and the heat has no 



j 

< 



So. | ■ 


x£!^QI 






1 T 






±zt:± 




50 —l 


\- zt - 




W *" ■ — 1 


z.r ± : 




3* 


\ .4 




pa 


tt T - 




' \ 


3 _ti 






2 l^El_ 


- 


IS -\ 


Si 3 | 






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_^^*sa taBrt= - 


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Atmospheric line 



A 10 30 30 40 50 60 70 So 90 i.jo 

Volume. 

Compression lines for air (dry), Adiabatic and Isothermal. 

Fig 10. 



time to escape by conduction. If no heat whatever is lost by any 
cause, the line will be traced over and over again by the indicator 
pencil, the cooling by expansion doing work precisely equalling 
the heating by compression. This is the line of no transmission 
of heat, therefore, known as Adiabatic. Fig. 10 shows these two 



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Tliermodynamics of the Gas Engine 41 

lines for air starting from atmospheric pressure and tempera- 
ture. 

The pressures at different points of the curve are related by the 
equation 

pv y = constant. 

The pressure when multiplied by the volume raised to the y power 
is always constant. 

The powers is the ratio between the specific heat of the air at 
constant pressure and its specific heat at constant volume. Ac- 
cording to Rankine 

y = 1-408 for air. 

Imperfect Heat Engines, — For a complete description of the 
working cycle of perfect heat engines, the reader is referred to 
works upon the steam engine, which contain the fullest possible 
details both of reasoning and results. 

The working cycles of practicable heat engines are always im- 
perfect, that is, the operations are such that, although perfectly 
carried out, the maximum efficiency possible by the second law of 
thermodynamics could not be attained by them. Each cycle has 
a maximum efficiency peculiar to itself, which is invariably less 

than T ~ T , but which does not necessarily vary with T 1 and T. 

It does not always follow that increase of the higher tempera- 
ture causes increase of efficiency ; conversely, it does not always 
follow that diminution of the upper temperature causes diminution 
of efficiency. Under some circumstances, indeed, the opposite 
effect is produced— -increase of the upper temperature diminishes 
efficiency, while its diminution increases it, of course within certain 
limits. 

All the gas engine cycles described in the previous chapter are 
imperfect in this sense, but all are practicable. It follows that if 
any one of them gives a higher efficiency than another in theory, 
it will also do so in practice, provided the practical losses do not in- 
crease with improved theory. 

It is necessary before discussing the practical losses to see how 
the cycles compare with each other, if each be perfectly carried 
out The results obtained can then be modified by examination 
of the way in which unavoidable practical losses affect each cycle. 



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42 The Gas Engine 



Efficiency Formula. 

If H is the quantity of heat given to an engine, and H 1 the 
amount of heat discharged by it after performing work, then, the 
portion which has disappeared in performing work is H — H 1 , 
supposing no loss of heat by conduction or other cause, and the 
efficiency of the engine is 

H 

Type i. — A perfect indicator diagram of an engine of this kind 
is shown at fig. 1 1 : the line a be is the atmospheric line, represent- 
ing volume swept by the piston, the line a d is the line of pressures. 
From a to b the piston moves forward, taking in its charge, at 
atmospheric temperature and pressure; at b communication is in- 
stantaneously cut off, and heat instantaneously supplied, raising 
the temperature to the maximum, before the movement of the pis- 
ton has time to change the volume. From e, the point of maxi- 
mum temperature and pressure, the gases expand without loss of 
heat, the temperature only falling by reason of work performed 
till the pressure again reaches atmosphere. The curve e c is 
therefore adiabatic. In all cases let 

/ be the initial temperature of the air in absolute degrees Centi- 
grade. 

t the absolute temperature after explosion or heating. 

t 1 the absolute temperature of the gases after adiabatic ex- 
pansion. 

/ the atmospheric pressure. 

p the absolute pressure of the explosion. 

v the volume at atmospheric temperature and pressure. 

v the volume at the termination of adiabatic expansion. 

In the particular case of diagram fig. n, where the expansion 
is continued to the atmospheric line, the formula expressing the 
efficiency is very simple. Calling k„ the specific heat of air at 
constant volume, and k, the sp. heat at constant pressure, then 
the heat supplied to the engine is 

h = k,(t-/), 



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Thermodynamics of the Gas Engine 



43 





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44 The Gas Engine 

and the heat discharged from it is 

therefore efficiency is 

k»(t-/)-k , (t'-/) 

M?T > 

and 5*=j> 

therefore e= i —y I -— ^ J. (i) 

It is evident that for every value of t there is a corresponding 
value of t 1 , which increases with the increase of t. If t 1 is 
known in terms of t, then the calculation of efficiency is very 
rapid, as all that is required is a knowledge of the maximum 
temperature of the explosion to calculate the efficiency of an 
engine using that maximum temperature, and perfectly fulfilling 
this cycle. 

For any adiabatic curve, the pressure multiplied by volume 
which has been raised to the j>th power is a constant; there- 
fore 

p, vf -=p v y (see diagram, fig. 1 1), (a) 

x p p 

and t = — which, as/ = /„ is the same as — ; 

t P A 



also £ s 

v. 



.*. in equation (a) t may be substituted for p„ / for /„ / for v„ and 
r 1 for v, giving 



-'(-f)' 1 



<*) 



In most engines of this type the expansion is not great enough 
to reduce the pressure to atmosphere before opening the exhaust 
valve ; it is therefore necessary to give formulae where the best 
condition is not carried out Fig. 12 is a diagram of a case of 
this kind. 

The pressure at the termination of the stroke has fallen to/„ 



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T/iermodynatnics of the Gas Engine 45 

and the temperature to t 1 . The heat supplied to the engine is 
the same as in the first case 

h = k v (t- /). 
The heat discharged by it cannot be so simply expressed. 
Suppose the hot gases at the pressure p to be allowed to cool by 
contact with the sides of the cylinder at constant volume till the 
atmospheric pressure/ is reached, then the temperature 

,i = T i t 

A' 

v 
or in terms of volume and / t l = /, 

and the heat lost is k^ (t 1 — t x ). 

The heat to be still abstracted before the air returns to its 
original condition at /, and pressure p is 

K,(/>-/). 

Total heat discharged by exhaust, therefore, 

h 1 = k v (t 1 - /') + k,(/ 1 - /). 
The efficiency consequently is 

E - K y (T - /) - {K, (T» - /') + K, (/' - /)} 

= (T« - g) + J(fi - /) ( . 

T - / U/ 

In this case there is no fixed relationship between t the tempera- 
ture of the explosion, and t 1 the temperature of the gases at the 
termination of adiabatic expansion. As the expansion is more or 
less complete, so does t and t 1 change. In no case, however, 
can the efficiency be so great as that in the first case. 

Type 2. — A perfect indicated diagram of an engine of this type 
is shown at fig. 13. Although the cycle requires two cylinders, 
producing two diagrams, they are better compared when super- 
posed. The whole diagram may be supposed to come from the 
motor cylinder, the shaded portion of it representing the available 
work of the cycle, and the unshaded part, the part done by the 
compressing pump. The atmospheric line is a be. The pump 
volume is a &, the motor volume is a c. The pump takes in the 
volume a b at atmospheric pressure ; it compresses it into an 



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46 The Gas Engine 

intermediate receiver, the compression line (adiabatic) is bf y 
passing into receiver, line fe. From the receiver it enters the 
cylinder at the constant pressure of compression on the line efg y 
supply of heat cut off at g. Then expansion (adiabatic) to the 
point c atmospheric pressure. The part bfgc is the part avail* 
able for work, the part bfe a representing the work of the com- 
pressing pump, which is deducted from the total motor cylinder, 
diagram aegc. 

The total volume of air passed through the pump is v„ volume 
swept by motor cylinder, v. So far as the heat operations are 
concerned, the part of the diagram to volume v c may be disre- 
garded ; it represents the pressing of the compressed charge into 
the reservoir after reaching the maximum pressure of compression 
(it is called v c because it is volume of compression). The admis- 
sion to the motor cylinder is identical, so that work done in pump 
in that part equals work done upon the motor piston. 
In addition to the letters used in type i, 

v c is volume of compression. 

v p volume at point g on diagram. 

p c is pressure of compression. 

/, is temperature of compression. 

The temperature, volume, and pressure letters are figured 
below the diagram to make matters clear. Compression is carried 
on from volume v at atmospheric pressure and temperature to 
volume v c at pressure /, and temperature t a the curve being 
adiabatic. 

After compression, heat is added without allowing the pres- 
sure to increase, but the piston moves out till the maximum tem- 
perature t is attained, and the supply of heat being completely cut 
off, adiabatic expansion follows till the atmospheric pressure is 
reached ; the exhaust valve is then opened, and the hot gases dis- 
charged. 

It is evident that as the pressure is constant, while heat is 
being given, the amount of heat given to the engine in all is 

h = k, (t - /,), 
and the heat discharged from it is also at constant pressure, 
h 1 = k, (t 1 - /). 



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Thermodynamics of the Gas Engine 



47 



•* U^o VjSs^ 









J 


» — ' 




c 








.2 


^ 




•►■ 


*33 


/ 






c 








8. 


/ 






X 


/ • ' ^ 






V 


/ 


— 




0) 


/ 








i 






jy 


/ 














13, 


/ 






E 


/ 


- 


- 





/ 






U 


/ 




. *v 


-/ 




S 




— 












r 


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8. 

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ff«K«K«*8S 



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48 The Gas Engine 

The efficiency is therefore 

T 1 - t 

- ' - T _,, (4) 

The compression and expansion curves being adiabatic, 
Compression p e v? = / v/ 9 
Expansion p c vf = p,v y \ 

so that 5l s Ul. / a ) 

and*<=^also*'<=' 

^ t # T 1 

Substituting in equation (a) 

*< = L 

T T 1 ' 

As the efficiency is 

T 1 -/ 

it may be either — i— -or=i — (5) 

That is, when expansion is carried to the same pressure as existed 
before compression, the efficiency depends upon the compression 
alone, / being the temperature before compression, and t c the tem- 
perature of compression. The efficiency being 1 — -, the greater 

the temperature t e the less is the fraction -, and the more nearly 

does E approach unity. 

In most working engines of this kind, the expansion is not 
continued long enough to make the pressure after expanding fall 
to atmosphere ; so that the efficiency is never so great, as when that 
is done, a greater portion of the heat is discharged than need be. 



and *' = -'. 



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Thermodynamics of the Gas Engine 49 

The modification of the formulae is precisely as in type 1 for 
similar circumstances. A diagram of the kind is shown at fig. 14. 
The temperature t x is found as before : 

A 
The heat supplied to the cycle is as before : 

H = K,(T-/ f ), 

and the heat discharged is 

h 1 = k* (t 1 - Z 1 ) + k, (/ l - /). 
The efficiency is 

I (T l _/') + (/>-/) 

h-.-Z — (6) 

Although there is no fixed proportion between the efficiency and 
the temperature of adiabatic compression, it is evident that e in- 
creases with increase of t? 

Type 3. — A perfect indicator diagram of an engine of this type 
is shown at fig. 15. As in type 2, the diagrams of pump and 
motor are combined, the whole diagram being that given in the 
motor cylinder, but the shaded portion only represents the avail- 
able work. The atmospheric line is a b c. The pump volume is 
ab, the motor cylinder volume is a c. The pump takes in the 
volume a b at atmospheric pressure, compresses it on the adiabatic 
line bf and into a receiver on the line/^. The compressed gases 
enter the motor cylinder on the line gf y heat is added instantane- 
ously, and the pressure rises on the line fe. Supply of heat cut 
off at e and the expansion line e c is adiabatic. The total diagram 
in the motor cylinder is a g f e c> but the portion agfb is 
common to motor and pump ; the available work is therefore 
bfec. 

The total volume of air passed through the pump is v ; the 
volume after adiabatic compression, from atmospheric pressure / 
and temperature / to pressure of compression/,, and temperature 
t a is v c Heat is supplied at constant volume v c till the maximum 
temperature of the explosion t is attained. The piston then 
expands the hot gases adiabatically from temperature t to t 1 
and pressure p„ to pressure p„ which in this case is equal to 
atmosphere. 



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5o 



The Gas Engine 



The heat is discharged in passing from volume v to v at con- 
stant pressure of atmosphere. The part of the diagram from 
volume v c to zero may be disregarded as it is common to both 
pump and motor. 

The heat supplied to the cycle is 

H = K„ (T-/ f ). 




S3c3g.v8S>%&8 2 



S9JT1SS9JJ 



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Thermodynamics of the Gas Engine 5 1 

Heat discharged 

h 1 = k > (t 1 -/). 
The efficiency is 

It is evident that for any maximum temperature t and com- 
pression temperature t c there is a temperature t 1 at which the 
expansion adiabatic line falls to atmosphere. It will much sim- 
plify subsequent calculations to establish the relations between t, 
/ t , / and t 1 . 

fjdJ =p v y axiApp? =/z>/ and as/,=/, 

A */ 

but -=1' so that ^=^ 

?„ ' A ** 

and ^ = 1 so that 1 = (^Y. 

t 1 in terms of t, /, and / is therefore 

(8) 



-'£)'■ 



Although this is the best case for the third type it is not the 
one commonly occurring in practice ; no engine has as yet been 
arranged to expand the gases after explosion to the atmospheric 
pressure. 

Fig. 1 6 is a perfect diagram of the most common case, namely, 
when the expansion is carried only so far that the heat is dis- 
charged when the volume is the same as that existing before com- 
pression. The formula of efficiency is exceedingly simple, and 
leads to a very apparent and nevertheless somewhat paradoxical 
result 

The heat supplied to the cycle is 

h = k v (t - / c ), 
and the heat discharged is 

h 1 = k„ (t 1 - /;, 



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52 



T/te Gas Engine 



because the volume of the air is the same as that existing before 
compression, and therefore the heat necessary to bring the fluid 
back to its original state can be abstracted at constant volume. 



£ k 




VoLU.MES. 

t absolute temp. r C. at b p absolute pressure at b 
tc 



f k 

e vo 


M It 

volume at 


/ 
e 

b 


C V 
TC 

Here v = v. 


•i 


c 
f 



Fig. i 6. 
Type 3. Perfect diagram. Expansion to same vol. as before compression. 

The efficiency is 

r _k.(t-/,)-Mt*-/) 
E -~ Mt-/,) 



T 1 - / 

T ~~- t 



(9) 



As both curves are adiabatic, and pass through the same volume 
change, 

t 1 _ / 

T "7/ 



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so that 



Thermodynamics of the Gas Engine • 53 

t 1 - / t 1 / 



T - t c T t e 

The efficiency may therefore be expressed 



e = 1 - Z- or 1 - J- (10) 

T t c 



or 



- (r - 



That is, the efficiency depends upon the ratio between the 
initial temperature and the temperature of adiabatic compression 
only, t, the temperature of explosion, may be any value greater 
than t a without either increasing or diminishing the efficiency. 
In this case 

T 1 = -. 
t c 

There is still another case of this type of cycle to be con- 
sidered, when the expansion is continued beyond the original 
volume before compression, but not carried far enough to reach 
atmospheric pressure. Fig. 17 is a diagram of the kind 

The heat supplied to the cycle is still 
h = k„ (t - t c ). 

The heat discharged may be found as in a similar case with 
types 1 and 2. 

Total heat discharged is 

hi^Mt 1 - /») + K,(fl -/). 
The efficiency is 

E a Mt-Q - (M t 1 - * l ) ± k> (/ ! - /)} 
k v (t - t c ) 

= 1 -<? x -fi)+y(fi-i) (ll) 

T — t c V ' 

Here then is no constant relationship between t 1 an^ t ; 
the value of the cycle lies between cases 1st and 2nd. The 
efficiency is less than in the first case, but greater than in the 
second. 

Type 1 A.-~In this type of engine the efficiency cannot be 
stated in terms of temperature directly because of the nature of the 
perfect cycle. 



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54 



The Gas Engine 




I I I I I I I I I 

'9 I 'i 'a '3 4 '5 o "7 



'3 '4 "5 6 '7 

x'o 

Volumes. 
t absolute temp. C C. at b p absolute pressure at b 

* „ „ / pc „ „ / 

P° „ » * 

t „ „ * r* volume at b 

T 1 „ r » „ c 

vc ,. / 

Fig. 17. —Type 3. Perfect diagram. Incomplete expansion. 




7 a 9 
Fig. 18. — Type ia. Perfect diagram. Limited expansion. 



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TJiermodynamics of the Gas Engitie 55 

The expansion line is adiabatic, and the compression line 
whereby all the heat is discharged is isothermal. 1 

Fig. 18 is the theoretical diagram of such an engine. The 
scale is altered from previous diagrams because of the great ex- 
pansion. 

There is no compression previous to the addition of heat, the 
heat is added at constant volume v„ which is the volume of the 
charge. The pressure rises with the temperature from atmos- 
pheric pressure / and temperature / to maximum pressure p„ and 
temperature t. From t the expansion line is adiabatic, and is 
continued far enough to reduce the temperature again to /. The 
piston then returns, compressing the gases at the temperature / till 
the original volumes and pressure / are attained. 

For any two temperatures / and t there is evidently a 
constant relationship between the available work and work dis- 
charged as heat. As in expanding from highest to lowest tem- 
perature the temperature falls from t to /, the whole area of 
the diagram t v v /, may be taken as the heat supplied to the 
cycle. 

The heat rejected is discharged at constant temperature /, and 
is equivalent to the area v v tt 

For any adiabatic curve the area Tv vt\s 

area = * (p, v — p v). (12) 

For any isothermal 

area^z;// = pv Log. t — . (13) 

The efficiency is therefore — 

J_(i>, - A*') " (/». Log. c|) 



E-'- 



y- * 



(M'.-A*') 



{y- 0(/*.Log-«^) 



-' rX-P.v (I4) 

1 In Dr. A. Witz's able work, Etudes sur Us moteurs & gau tonnant, he falls 
into the error of supposing both expanding and compression lines of this type adi- 
abatic, and he accordingly greatly over-estimates the efficiency proper to it. 



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56 Tlie Gas Engine 

but, as the line of compression discharging heat is an isothermal, 
that is, the temperature is kept constant at / during compression 
from the lowest pressure to atmosphere, 
pv 9 = p 9 v (Boyle's law). 
The efficiency may therefore be written 

Cy-i)(>.Log.c^) 
E = i 2 v j± 

ty-i)/Log. c^ 

then Z = * = (*-Y~ l .if-frjA 

The efficiency can therefore be given entirely in terms of t and t : 

(y-i)/Log. '(j)^ 'Log.*£ 
e=i- — _^ =1^. i. (, 5 ) 

T— / T — / D 

In the case where the expansion is not carried far enough to 
bring the temperature of explosion down to the temperature of the 
atmosphere, the efficiency can be found by using the formulae 
12 and 13 to get proportions of available and total work, and then 
get from the nature of the compression curve the total heat dis- 
charged. As this is variable it will be better to study it from a 
numerical example later on. 

The diagram given is the best possible for this kind of cycle. 

Efficiency Formula for the Different Types. 
The general formulae for efficiency of the four kinds of cycle 
are as follows. 

Type i, 1st Case : 

t 1 - t 

t 1 in terms of t and /: 



,„®i 



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Thermodynamics of the Gas Engine 


57 


2nd Case : 




T — / 


(i7) 


Type 2, ii/ C<w* : 






(18) 


also e = 1 — —. 




2nd Case : 




I ( T i - /») + (/1 - /) 

e — 1 — J 

? -t c 


(19) 


Type 3, irf Case : 




T l — / 
e = 1 — y 


(20) 


t 1 in terms of t and / : 




T > = / (1) ; 




2nd Case : 




E=I- T '-'. 


(21) 


also e = 1 — — 





yd Case : 

E « I - (T 1 - /*) + jy (/' - / ) 

T - < * (22) 

Type i A : 

/(j/-i)Log.£ (^)^ /Log.^ 
e = 1 - )LL = 1 1. (23) 

T — / T — / V 0/ 

Those formulae will be found very convenient in rapidly calcu- 
lating the theoretical efficiency for any kind of diagram, but they 
do not throw much light upon the relative advantage of the differ- 
ent types. In type 1, for instance, it is apparent that efficiency 

increases with increase of temperature because the fraction 



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58 The Gas Engine 

becomes less with increase of t, but it does not rapidly become 
less because t 1 also increases with increase of t. 

In type 2, 1st case, the efficiency is quite independent of t, 
and is dependent only on the ratio between / and t Q or v and v c . 
Increase of t (maximum temperature) increases the available 
portion of the engine diagram, and therefore the average pressure, 
but without altering the efficiency. 

Type 3. — With this type it is easy to see (1st case) that the 
efficiency is greater than in type 1, but only a numerical example 
will show the proportion. 

In the second case it may be greater or less than in type 1, 
depending altogether on the amount of the compression. 

To obtain a clear idea of the relative values of the efficiencies, 
it is necessary to calculate a few numerical examples. 

Calculated Examples of Efficiency of the Types. 

Numerical Examples, — Using air as the working fluid, the 
value of y, the ratio of specific heat at constant volume to specific 
heat at constant pressure is i'4o8. 

Jk =y = 1-408. 

The gaseous mixture used in a gas engine differs considerably 
from pure air in its composition, and consequently in the ratio 
between specific heat at constant volume, and specific heat at con- 
stant pressure, but it is advisable in the first place to consider the 
cycle as using air pure and simple. So many circumstances 
modify the theoretic efficiency in actual practice that they can be 
best considered after studying the simpler cases. 

The temperature 1600 C. is a very usual one in the cylinder 
of a gas engine, and it will be calculated in each instance as the 
maximum, 17 C. being taken as atmospheric temperature. 

A similar set with 1000 C. as the maximum will be calcu- 
lated to show in each case the change of efficiency, if any, with 
change of maximum temperature. 

Type i. — 1st Case, The expansion is continued to atmos- 
pheric pressure. 

Taking t = 1600 C. = 1873 absolute. 
/= i 7 °C. = 290 „ 



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Thermodynamics of the Gas Engine 59 

Then t 1 = the temperature after adiabatic expansion to 
atmospheric pressure. 

T' -/(!)> (2) 

t 1 = 290 ( — Z3 jr^s = 1090 absolute. 
The efficiency is 

e = i -.y T — ' = 1 - x-408 x f° - 2 *L _ 0-29 

T — / 1873 — 290 y 

e = 0*29 with maximum temperature of 1600 C. 
Taking the maximum temperature of explosion as 1000 C. 

Absolute 
T = I273 = IOOO° C 

/= 290°= i7°C 
then t 1 = 82 9 . 

e = 1 - 1-408 8 29_r_19?_ . . 2 
1273 — 2 9° 
E *= 0*23 with maximum temperature of explosion as 1000 C. 
In this cycle the efficiency evidently increases with increase of 
the temperature of the explosion, but not in proportion to the 
increase of temperature ; a change of maximum temperature from 
1000 to 1600 C. only causing the efficiency to rise from 0*23 
to 0*29. That is, at the first temperature, 23 heat units out of 
every 100 given to the cycle will be converted into work, 
while with the second much higher temperature, only 29 units of 
100 will be converted into work. 

The second case of this type is the one most commonly occur- 
ring in practice. The cylinder is so arranged that the charge is 
taken in for half- stroke, the explosion then occurs, and the piston 
completes its stroke, expanding the heated gases from one volume 
to two volumes 

In the diagram, fig. 12, suppose volume v to be equal to 
2 v„ and 

t = 1873 absolute. 
/« 290 
To get t 1 , 

T 1 \vj T \VJ 



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6o The Gas Engine 

t 1 = 1873 I -j = 141 1° absolute. 

To calculate efficiency t x is still required ; it is, in terms of 
volume and /, 

Z 1 = -t = ?2oo = 580 absolute. 
The efficiency can now be obtained from formula (17). 

E - 1 -(T'-' I )+J'(' 1 -') 

= 1 (1 4" - 5 go ) + 1*408 (530 - 290) 
1873 - 290 

- 1 - 8 3LiLL4o8j<_i?o = c . 22 nearl 
1583 y 

For this case e = 0*22, 

showing the effect of limiting the expansion and discharging at a 
pressure above atmosphere. 

Taking the same ratio of expansion and the lower maximum 
temperature of 1000 C. 

t = 1 2 73 absolute. 
/ = 290 

_ J = 1273 ( - J = 959 absolute, 

and t x is still 290 x 2 = 580 absolute. 

Therefore e = 020. 

Here the diminution of efficiency due to diminished expan- 
sion is not so great as in the first, or rather the higher, tempera- 
ture, 

with complete expansion iooo C. giving 0*23, 
„ limited „ 1000 C. „ 0*20 ; 

with the higher temperature of 1600 G, 

with complete expansion 1600 C. giving 0-29, 
„ limited „ 1600 C. „ 0-22. 

It is evident from these results that where the amount of ex- 



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Tlurmodynamics of the Gas Engine 6 1 

pansion is from one volume to two volumes, as in the Lenoir and 
Hugon engines, the efficiency does not substantially improve with 
increasing temperature. 

Type 2. — 1 st Case, Where the expansion is carried far enough 
to reduce the working pressure to atmosphere, the efficiency of 
this kind of engine is quite independent of the temperature of 
combustion. This is shown by Professor Rankine • in his work on 
the steam engine. Whether the heat added after compression 
be great or small in amount, the proportion of it which is con- 
verted into work is stationary. 

The compression most commonly used in this kind of engine 
is 60 lbs. per sq. in. above atmosphere, 75 lbs. per sq. in. absolute, 
taking the atmospheric pressure as 15 lbs. per sq. in. 

The compression is, as before stated, adiabatic ; no heat is 
lost or gained. The temperature rises simply because of work 
performed upon the air. 

Let 
Atmospheric temperature and pressure (absolute) t,p = 290 - 15 
Compression, „ „ „ ' rt A= —75 

t c = 290 M-5 J = 462*5° absolute, 

2QO 

e = i - — ?— = 0-37 
462-5 

E = C37. 

This result is much better than any obtained with the first 
type. It holds equally good for all combustion temperatures ; 
with either iooo° C. or 1600° C. the efficiency would still be 
0*37, so long as that degree of compression was used. With a 
higher compression the efficiency increases ; 100 lbs. per sq. in. 
above atmosphere is quite a workable degree of compression. It 
is instructive to calculate the efficiency with this pressure : 

1 The Stejm Engine, Prof. Rankine, p. 373, Formula (7). 



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62 The Gas Engine 

t — 290° absolute. 

/ = 15 lbs. per sq. in. absolute. 

P< = * * 5 » » » »> 

\V = 524 ° nearly ' 
e=i- 2 -9? = o-45. 

E = 0-45. 

This type is evidently much superior to the first type, as it is 
capable of greatly increased efficiency by the mere increase of 
compression. 

In the engines in practice expansion has not been carried far 
enough to give the results calculated above. It has been usual to 
construct the engine so that the compression pump is one-half of 
the volume of the motor cylinder, that is, the ratio of the expan- 
sion is from one volume to two volumes at atmosphere. Taking 
first a compression of 60 lbs. per sq. in. above atmosphere with this 
proportion between the volumes at atmosphere, and the highest 
temperature as 1600 C, then (diagram, fig. 13) 

t = 1873 absolute 

/ = 290 

/,= 462-5° - 

t x = 290 x 2 = 580. 

Before getting t 1 it is necessary to get the volume v p at the 
highest temperature. It is 

T 

v p = v c - 

and v c = v (L. y — 1 fllV" 7 ^ =0318 

.\ v > = 0-318 if^i = 129 
4625 

and t 1 = t ( 7 ^) yi = 1873 flJ9\ 0¥ * = 1566° absolute. 

The efficiency can now be found by formula (19) 

^(t 1 - /*) + (/i -/) I( I5 66- 5 8o) + (58o-2 9 o) 

e= i — y - — . = i ~y 

T — /, 1873 — 462*5 



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Thermodynamics of the Gas Engine 63 

071 (086) + 200 
= 1 '- — 5z — lj. — z. = 1 — 070 = 0.30 

1410*5 

E =■ 0*30. 

Here the insufficient expansion has caused the efficiency possible 
from the compression to fall from 0*37 to 0-30. 

Calculating in the same way for the greater compression of 
100 lbs. per sq. in. above atmosphere, with expansion ratio between 
compression and motor cylinders of two, it is found that the result 
is improved. 

Here v c = 0*235 vol. 

and z> = 0*841 vol. 

t' = t (2?) *"' = 1873 (^) ^ = 1318 absolute. 

T = 1873 

/ = 290 
/»= 580 
'<= 524° 

The efficiency is therefore 
, „ T _ J (Tl " /1 > + < /1 " / > = i 071 (i 3 i8- 5 8o)+(58o-29o) 

T-t e 1873—524 

= j - 07UI 73«jL?9o =i _ JlA = 0-40 
1349 r 349 

E = 0*40. 

The greater compression has greatly increased the efficiency 
while leaving the proportion of the two cylinders unaltered. 

Still using the same cylinders, the efficiency with compression 
of 60 lbs. above atmosphere and a maximum temperature of 
1000 C, is 

e = 0*36 nearly, 
the data being 

t x = 906 t = 1273 

^=580° / = 290 



/, = 462 , 
v = 2 

7><= 0-318 V p = C87. 



volumes 

ZU= I V = 2 



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64 The Gas Engine 

Using the higher compression ioo lbs. above atmosphere with 
iooo C. as highest temperature 

e = 0*44. 
Data: t ! = 763 t =1273° 

/i = 580 / = 290° 

4~ 5*4° 
Vol. : v = 1 v ■=■ 2 

7' f = 0-235 7>= 0"57 

In this kind of engine the best result is always obtained when 
the expansion is carried to atmospheric pressure. The necessary 
proportion between the two cylinders, to accomplish this, depends 
on two things : the temperature of compression, and the tempera- 
ture of combustion. The ratio between the cylinders should be 

T 

With a temperature of compression of 46 2 °, for instance, 
and a maximum of 1873 absolute I 1 '-? = 4*05) the volume of 

the motor cylinder would require to be 4-05 times that of the 
pump. With the increased compression giving 524 absolute 

{ l —l$-= 3*57) ratio of motor to pump 3*57 to 1. 

With the lower maximum temperature of 1273 the ratios for 
the two compression values are 

L 2 73 _ 2 .- 5 I 2 73 _ 2 . 4:5 nearly. 

462 ° 524 HJ 7 

These figures explain why the efficiency varies so much with 
two cylinders of ratio 1 to 2 with change of maximum temperature 
and compression. 

Type 3. — 1st Case. In this case expansion is carried to atmo- 
sphere. It is evident from the formulae that efficiency varies to 
some extent with maximum temperature of the explosion. 

Taking first a maximum temperature of 1600 C, as in the last 
type calculated, with a pressure of compression 60 lbs. above 
atmosphere, 

The data are as follows : 

Temperatures 7=1873° /=29o 

t r = 462. 



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Thermodynamics of the Gas Engine 65 

t 1 in terms of t and /, t t is (see p. 57) 

T' = 7 8 3 °. 

The efficiency therefore 

E = x -,HL=± = ! - x. 4 o8 783 - 290 
T - t c * 1873 - 462 

E = 051. 

With compression 100 lbs. above atmosphere, 

4 = 524° 

and t 1 is therefore t 1 = 200 ( Ii~13\f^8 — 7I 6° 

\524y 

and e = i- 1-408 545 - 290 

1873 - 524 
e = 0-55. 

Taking, next, 1000 C. as the highest temperature, first with 
the lower compression, and after with the higher compression, 
with 60 lbs. compression t 1 is 595 absolute 
with 100 „ t 1 is 545° „ 

e = 0-47 at 60 lbs., e = 0-52 at 100 lbs., with 1000 C. 

In this case the efficiency varies both with the maximum tem- 
perature of the explosion and the compression temperature previous 
to explosion. A glance at the numbers placed together will show 
clearly the relationship. 

Max. temps, in °C. ... 1600 1600 1000 1000 
Pressure of compression above atmo- 
sphere 60 lbs. 100 lbs. 60 lbs. 100 lbs. 

Efficiency 0*51 073 0*47 0*52 

2nd Case. — Here the expansion after explosion is not carried 
on far enough to reduce the pressure to atmosphere. It terminates 
when the volume is the same as existed before compression, that is, 
the volume swept by the motor piston in expanding doing work is 
identical with that swept by the pump piston in compressing up to 
maximum pressure. Pump and motor are equal in volume. To this 
case of type 3 belong all compression engines in which the motor 
piston compresses its charge into a space at the end of the cylinder. 

F 



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66 The Gas Engine 

In this case, as in case i, type 2, the theoretic efficiency of the 
engine is quite independent of the maximum temperature of the 
explosion. So long as the volume after expansion is the same as 
that before compression, it does not matter in the least how much 
heat is added at constant volume of compression ; whether only a 
few degrees rise occurs or 1000 or 2000 , it is all the same so 
far as the proportion of added heat converted into work is con- 
cerned That proportion depends solely upon the amount of 
compression. 

For 60 lbs. adiabatic compression, temperature 462 absolute, 
theefficiency is 0-37 ; for 100 lbs. above atmosphere it is 0*45. Given 

by the formula e = 1 — -- . (See p. 57.) 

*< 

e depends absolutely upon the temperature of the atmosphere 
and the temperature of compression / and t c . If the relative 
volumes of space swept by piston and compression space be known, 
then the efficiency can be at once calculated. 

$rd Case. — Here the expansion is carried further than the 
original volume before compression, but not far enough to reduce 
the pressure to atmosphere. Efficiency is always less than in the 
first case with corresponding temperature of explosion and compres- 
sion, but greater than in the second case. It is found by the 
formula : 

T - t c 

t x depends on the relationship between the volumes v and v the 
volume at atmosphere and the volume of discharge after expansion, 
it is always : 

t 1 is also found by the same method as in types 1 and 2. It is 
better to postpone calculating any particular case of this at present, 
as no engine doing this has yet got into public use, and it can be 
considered further on in discussing the effect of increased expan- 
sion in the actual engines. 

Type 1 A. — The efficiency of this type of heat cycle depends 
to a considerable extent upon cooling during the return stroke ; 
in its best form, cooling at the lowest temperature during isother- 



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Thermodynamics of tlie Gas Engine 67 

mal compression, it cannot be carried out without introducing the 
very disadvantages with which the hot-air engine was saddled, 
namely, a dependence upon the slow convection of air for the 
discharge of the heat necessarily rejected from the cycle. The 
rapid performance of this operation is impossible, and accordingly 
it is hardly fair to compare this type with those preceding ; they 
could all of them be greatly improved in theory by introducing 
greater expansions and cooling by convection at the lowest tempe- 
rature, but all at the expense of rate of working. The efficiency 
of type 1 A, will be found to be high'; but it is to be kept con- 
stantly in mind that the penalty of slow rate of work was fully 
exacted in the practical examples of the kind in public use. They 
are exceedingly cumbrous, and give but a trifling power in com- 
parison with their bulk and weight The efficiency in this type is 
dependent upon t and / only. 

(v - 1) / Log. £ (*V--. / Log. e 1 

Take first t = 1873 

/= 290 

Es =i-- 9 °- X r8 ^ 
1583 
e = o*66. 
This is a very high efficiency, but it is obtained by using an 
enormous expansion, 

— = ( — J*-" 1 = 967 nearly. 

The piston must move through nearly 100 times the original 
volume of the charge before the temperature is reduced to the 
temperature existing before igniting ; in passing back to unit 
volume the gases must be supposed to keep at / by the cooling 
effect of the cylinder walls. 

When t = 1000 C = 1273 absolute, 

/= i 7 °C. = 290 „ 
the efficiency is 

e = 0-56, 
and the expansion required is not so great, being 37-5 volumes. 



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68 



The Gas Engine 



The actual ratios of expansion used in practice have not ap- 
proached those proportions, and will be considered while discuss- 
ing the diagrams taken from engines of this type. 



Comparison of Results. 

The two maximum temperatures used, 1600 C. and iooo° G, 
with the lowest temperature, 17 C, give in a perfect heat-engine, 
efficiencies 

1600 C. = 0-85 nearly, 

1000 C. = 077 „ 

One case in type 3 comes nearer to a perfect heat-engine than 
any of the others. To compare easily the following table will be 
useful. 

Table of Theoretic Efficiency. 





Max. temp. °C. 


Compression 


Efficiency 


Type 1. 




Temp. 1 Pressure 
abs.°C. above atmos. 




Expanding to atmosphere 


1600 


— 


— 


0*29 


11 •! 11 


1000 


— 


— 


0*23 


Expanding to twice volume 


1 1600 
\ 1000 


— 


— 


O a 22 


existing before ignition 


— 


— 


0*20 


Type 2. 










Expanding to atmosphere 


— 


462 


60 lbs. 


0'37 


■ • ti »i 


— 


524 


100 lbs. 


c"45 




/ 1600 


46a 


60 lbs. 


030 


Expanding to twice volume 


1 l6oo l 


524° 


100 lbs. 


0*40 


existing before compression 


1 IO °°o 


462 


60 lbs. 


0-36 




V 1000 


5*4° 


100 lbs. 


0-44 


Type 3. 










Expanding to atmosphere 


1600° 


462 


60 lbs. 


0-51 


11 •» 11 


1600° 


5*4° 


100 lbs. 


o*55 


it ji »* 


IOOO° 


462 


60 lbs. 


0-47 


11 ii 11 


IOOO 


524° 


100 lbs. 


0-52 


Expanding to the same 


1 - i 








volume as existed before 
compressing 


462 
5*4° 


60 lbs. 
100 lbs. 


o*37 
o'45 


Expanding to greater volume 


! Efficiency betwe 






than existed before com- 


en 1st and 2nd case 


s of this type 


pressing, but not enough 


f depending on 


ratio of expansion. 




to reach atmosphere 






Type 1 A. 








Expanding from max. temp. 


1600 




0-66 


to lowest temperature 


IOOO° 




0-56 



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Thermodynamics of the Gas Engine 69 

Comparing first the best results of each type, it is evident that 
type 1 is the least perfect as a heat-engine, giving back only C29 
of the total heat entrusted to it as mechanical work, and rejecting 
the rest of the heat Type 2 is distinctly better, giving a maximum 
efficiency of 0*45, or nearly half the heat converted into work. 

Type 1 A, with a heat conversion of o*66, is still better. 

It cannot be too constantly kept in mind that it by no means 
follows that the best theoretic efficiency will give the best result in 
practice. If gained at the expense of great volume or an imprac- 
ticable process, it may not be worth so much as a worse cycle 
where small volume of cylinder and an easy process make it more 
easily attainable. Type 1 A is at a great disadvantage in the 
matter of expansion ; it requires, as has been shown, expansion of 
967 and 37 -5 volumes respectively, so great that it is practically 
out of comparison as a workable cycle with the others. The 
other cycles vary in this respect also, but the variation will fall 
under the consideration of mechanical efficiency at a later stage. 
Type 1 A is so much out that it was necessary to mention it here. 

In type 1, the efficiency varies with the temperature of explo- 
sion, especially where the expansion is carried to atmosphere ; the 
difference, however, is not great, a very large increase of maximum 
temperature but slightly increasing the efficiency, 1000 C. giving 
0*23, and 1600 C. only 0-29, of heat conversion. When the 
expansion is limited to twice the volume at the moment of heat- 
ing, the effect of increasing temperature in increasing the efficiency 
is almost nil, 1000 C. giving 0*20 efficiency, and 1600 C. only 
0*22 efficiency. The conclusion to be drawn from the fact is this : 
in engines of the Lenoir or Hugon kind, with limited expansion, 
the economy is not increased by using high temperatures ; a weak 
mixture will give as good an indicated efficiency as a strong one. 

With type 2, the maximum efficiency is obtained by expand- 
ing to atmospheric pressure, and in this case it is quite independent 
of the temperature of combustion; it does not matter whether a great 
or small increase of temperature occurs at the pressure of compres- 
sion, the efficiency remains the same. That is, whether much heat 
be added or little heat, the proportion converted into work de- 
pends on one thing only, that is, the amount of compression — the 
greater the compression the greater the efficiency of the engine. 



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yo The Gas Engine * 

The pressures of compression which have been calculated, are 
pressures which have been used for the kind of cycle in practice. 
The only limits to increasing compression are the practical ones of 
strength of engine and leakage of piston. The difference between 
efficiency at 60 lbs. and 100 lbs. compression above atmosphere is 
considerable, the first giving e = 0*37, the second e = 0*45. 

When the expansion is limited to twice the volume existing 
before compression the maximum temperature then, affects the 
efficiency, but not to such an extent as the compression. 

Type 3. — This is the best type of all from the point under con- 
sideration. The efficiency in the best form of it varies both with 
maximum temperature and pressure of compression. At 1600 C. 
maximum temperature and compression 60 lbs. per square inch 
above atmosphere, e = o'5i. At the same maximum tempera- 
ture but the higher compression of 100 lbs. above atmosphere, it 
rises. With maximum temperature of 1000 C. for these two 
compression pressures the efficiencies are e = 0-47 and e = 0*52. 
The best case of this type is not the one occurring in practice, in 
fact no compression engine of this kind has ever been much 
which expands to atmosphere. Usually expansion is only carried 
to the same volume as existed before compression, and there the 
efficiency is quite independent of the maximum temperature ; it 
is determined by compression solely as in type 2. 

For compression 60 lbs. per square inch above atmosphere it 
is 0-37, and for 100 lbs. per square inch above atmosphere it is 
0*45, the difference between types 2 and 3 in this case being, 
that type 2 expands its working fluid at the pressure of compres- 
sion, which remains constant, and the pressure falls to the pressure 
of atmosphere by the movement of the piston doing work ; in 
type 3 the heat is added to the working fluid at constant volume, 
pressure increasing, then expansion doing work, till volume 
before compression is attained. The one acts by increase of the 
volume of the working fluid by heat, the other by increase of 
pressure of the working fluid by heat. The one engine gives 
large volumes, low pressures ; the other small volumes, high 
pressures. 

In type 1 A, the change of volume required is so great that its 
efficiency cannot be fairly compared with the others. 



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Thermodynamics of the Gas Engine 7 1 

Conclusions. — The best cycle for great efficiency, excluding 
type 1 A, is produced by using compression in the manner of 
type 3. 

In any cycle with any definite expansion, increase of compression 
previous to heating produces increase of the proportion of heat 
converted into work. In some cases of compression cycles, increase 
of the highest temperature does not increase the efficiency; 
it may even diminish it 

There are cases in types 2 and 3 when the efficiency is quite 
independent of the maximum temperature, depending solely on 
the amount of compression employed 



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72 The Gas Engine 



CHAPTER IV. 

THE CAUSES OF LOSS IN GAS ENGINES. 

In calculating the efficiency of the different kinds of engines, it 
has been assumed that the conditions peculiar to each cycle 
have been perfectly complied with. In actual engines this is 
impossible ; it is therefore necessary to discover in what manner 
practice fails in performing the operations required by theory. 

The actual engines differ from the ideal ones in several 
ways : 

i. The working fluid loses heat to the walls enclosing it after 
its temperature has been raised to the highest point ; 

2. The working fluid often gains heat when entering the 
cylinder at a time when it should remain at the lowest tempera- 
ture; 

3. The supply of heat is never added instantaneously as is re- 
quired in some types ; 

4. The working fluid does not behave as a perfect gas ; owing 
to the complex phenomena of combustion, to some extent its 
physical state is changed during the addition of heat ; 

5. The admission, transfer and expulsion of the working fluid 
are not accomplished without some resistance, wire-drawing during 
admission, back-pressure during exhaust. 

The first cause of loss is by far the most considerable and will 
be considered first. 

Loss of Heat to the Cylinder and Piston. 

Although this is the most considerable source of loss in all 
gas engines, the stock of information in existence upon the subject 
is quite insufficient to justify any attempt to state a general law. 
So far as the author is aware, no experiments have yet been made 



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Tfie Causes of Loss in Gas Engines 73 

to determine the rate at which a mass of heated air, at from 1000 
to 1600 C loses heat to the comparatively cool metal surfaces 
which enclose it That the rate of flow is rapid is quite evident. 
Otherwise, it would be impossible to raise steam with the relatively 
small heating surfaces generally used in boilers. Before applying 
the efficiency values obtained to actual practice it is necessary to 
know at what rate a cubic foot of air at about 1600 C. in contact 
with metal walls at from 17 C. to ioo° C. will lose heat; also to 
know how that rate changes with change of temperature and 
density. Much is known of the laws of cooling at lower tem- 
peratures, but little positive data exist for temperatures so high 
as those occurring in the gas engine. A hot gas loses heat to the 
colder walls enclosing it mainly by circulation or convection. The 
conductivity of gases for heat is very slight, and unless in some 
way a large surface of the gas is exposed to the cooling surface, 
practically no heat would escape from the working fluid in the short 
time during which it is exposed in gas engines. Any arrangement 
which favours or hastens convection will therefore increase loss by 
increasing the extent of hot gaseous surface exposed to the walls. 
The smaller the surface to which a given volume of working fluid 
is exposed the less heat will it lose in a given time. So far as 
loss of heat is concerned then, the best type of engine is that 
which exposes a given volume of working fluid to the smallest 
surface in performing its cycle. Suppose that in the three types 
the pistons move at the same velocity, then that which requires to 
move through the smallest volume, the areas of the pistons being 
supposed equal, will take the shortest time to perform its cycle. In 
the first engine the piston moves through 27 vols., with the hot air 
filling the cylinder; the second, through 37 vols.; and the third, 
through 2*4 vols, (see diagrams 11, 13 and 15). As the volumes 
are proportional to the time taken to perform each cycle the 
third type has the best of it, the time of exposure of the hot 
working fluid being the least ; the second type is worse than 
the first. There is still another circumstance in addition to 
surface exposed and time of exposure, that is, the average 
temperature of the hot gas which is exposed. If the average 
temperature is lower in one type than in another during ex- 
posure to a given surface for a certain time, then obviously 



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74 The Gas Engine 

less heat will be lost in the one than in the other. Comparing 
the average temperatures it is found, that in the first the tempera- 
ture ranges from 1600 C. to 817 C. ; in the second from 1600 C. 
to 901 C. ; and in the third from 1600 C. to 510 C. The 
third will therefore show a lower average temperature than the 
others. Three conditions are requisite in the engine which is to 
lose the minimum of heat from its working fluid : 

1. In performing its cycle it should expose a given volume of 

its working fluid to the least possible cooling surface ; 

2. It should expose it for the shortest possible time ; 

3. The average temperature during the time of exposure should 

be as low as possible — 
which conditions are best fulfilled by the third type. In ad- 
dition to its advantage in theoretic efficiency it possesses the 
further good points in practice of proportionally small cooling 
surfaces, short time of exposure, and rapid depression of tempera- 
ture due to work done, consequently small loss of heat to the 
cylinder and piston. 

The diagrams, figs. 11, 13 and 15, have been selected from the 
others belonging to each type because the pressures, temperatures, 
and relative volumes closely correspond with those which would 
be best and at the same time readily practicable. 

The flow of heat really occurring in the gas engine cylinder 
will be discussed when the actual diagrams come under considera- 
tion ; meantime, it is sufficient to have proved that the third type 
will in practice give results more closely approaching its theory 
than the others. If in each case a constant proportion of the 
heat supplied were lost to the cylinder and piston, the ratio of the 
efficiencies would remain constant, and although it would be im- 
possible from present data to predict the actual values, yet 
the relative values would be known. 

Gain of Heat by the working Fluid when entering 
the Engine. 

In all types of gas engine it is found most economical to keep 
the motor cylinders as hot as possible ; they are generally worked 
at a temperature close upon the temperature of boiling water. 
This is done to diminish the loss of heat from the explosion. It 



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The Causes of Loss in Gas Engines 



75 



follows that if the working fluid is introduced at a lower temperature 
it becomes heated. In the first type, the charge should be admitted 
and remain at the lowest temperature until the moment of explosion, 
which is of course impossible if the cylinder is at ioo° C. As the 
piston itself is hotter than that, it may be supposed that the charge 
is heated to that point. 

Taking an extreme case and calculating the effect of having 
an absolute temperature of 390 for the lower limit, it will be 
found that the efficiency is diminished. In case 1, type 1, where 
the expansion is carried to atmosphere with a maximum tem- 
perature of 1873 absolute = 1600 G, the value becomes reduced 
to 0*23. 

With a maximum temperature of 1 2 73 absolute = 1 ooo° C the 
efficiency is 0*16. 

Type I. 



Initial temp, of working 
fluid 



17° C 
117° C. 

if C. 
117° C. 



Max. temp. 



i6oo°C. 
1600 C. 
iooo C. 
iooo°C. 



Efficiency 



0*29 
023 
0*23 
0*16 



Here heating, while introducing the charge will always cause 
diminution in efficiency, the proportion of loss being greater with 
the lower maximum temperature. At 1600 C. the loss is nearly 
one-fifth, while at 1000 C. it is close upon one-fourth. 

It is very difficult to say whether it is better to work with the 
cylinder hot or cold. The constructor finds himself in a dilemma ; 
if the cylinder is kept as cold as the surrounding air, then the 
hot gases cool more rapidly. If he keeps the cylinder hot to 
diminish this, the efficiency falls also. Experiment alone can 
decide the question. 

In engines of type 2 it is a usual proceeding to leave the 
compression cylinder entirely without water-jacketing, under the 
impression that heat is thereby saved ; the temperature consequently 
rises to very nearly that of compression, and the entering charge 
becomes considerably heated before compression. This is especi- 
ally the case if the admission area is small, and throttling occurs ; all 



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?6 The Gas Engine 

the energy of velocity of the entering gas becomes transformed into 
heat As in the previous case the charge may be considered to rise 
to ii 7 C. before compression. 

Where expansion is carried to atmosphere it has been shown 
that the efficiency is quite independent of the maximum tempera- 
ture, but is determined by one circumstance only — the amount of 
the compression. As 

f. = i * and / is the temperature absolute before compressing 

*c » » m » after „ 

and as ± = \* € \ ~y~ ", it follows that with a constant ratio between 

the pressures before and after compression, the ratio of temperature 
before and after compressing will also remain constant ; that is, 
the efficiency is not in any way affected by heating the working 
fluid, provided the same degree of compression is used. Increase 
of temperature previous to compression causes a proportional in- 
crease of temperature after compressing without in any way disturb- 
ing the ratio between them. 

This is an important, if in appearance a somewhat paradoxical 
fact, and it may be stated in another way : 

If an engine receives all its supply of heat at one pressure, 
and rejects all its waste heat at another pressure, after falling 
from the higher to the lower pressure by expansion doing work, 
the efficiency is constant for all maximum temperatures of the 
working fluid. 

The proportion of heat converted into work is not changed in 
any way by increasing the temperature before compressing, and 
if only one degree of heat be added after compressing, the same 
proportion of that one degree is converted into work, as would be 
done with any addition of heat however great. 

Where the expansion is not continued enough to reduce the 
pressure after heating, to atmosphere, as in the cases of this type 
which occur in practice, this is not quite true ; the compression 
still remains the most powerful element jof efficiency, but heating 
before compression produces some change, just as increase of 
temperature after compression produces change. The change is 

• See p. 57. 



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The Causes of Loss in Gas Engines 77 

not great, and it is always in the direction of improvement with a 
limited expansion. If the lower temperature / is increased, the 
compression temperature t c increases in proportion, and is ac- 
cordingly nearer the maximum temperature. The volume increases 
less on heating, so that the effect upon efficiency is the same as if 
the expansion had been increased ; the terminal pressure will more 
closely approach atmosphere, and therefore come nearer to the 
condition of maximum efficiency. 

In engines of type 3 the compression and expansion are often 
performed in the same cylinder. For this purpose it is necessary 
to leave at the end of the cylinder a space into which the charge 
is to be compressed. As the piston does not enter this space, a 
considerable volume of exhaust gases remains to mix with the fresh 
cold charge. Partly from this and partly from the heating effect 
of the cylinder and piston, the charge becomes considerably heated 
before compression. The temperature of 200 C. is not unusual. 
Here the simplest case is that where the expansion is continued 
to the same volume as existed before compression. The efficiency 
depends solely upon the amount of the compression ; for any 
given degree of compression it is constant, whether the addition 
of heat at constant volume after compression be great or small 

The efficiency is e=i — as in type 2 (see p. 57); and the two 

absolute temperatures vary in the same ratio, that is, if the charge 
is heated before compression, the temperature after compression will 
be increased in the same ratio. The two temperatures will therefore 
bear a constant ratio to each other, whatever the initial temperature 
may be, provided the compression is constant. Heating the charge 
before compression will consequently have no disturbing effect upon 
the theoretical efficiency.* 

Where the expansion is carried to atmosphere the case is 
different. The diagram (fig. 15) may be considered to be made up 
of two parts giving two different efficiencies, the sum of which in 
this case is 0*51. In expanding from the compression volume v. 
to the original volume v (compression 75 lbs. per square inch) 

• It is here necessary to distinguish between theoretical and practical efficiency. 
Heating before compression diminishes efficiency in practice by increasing max- 
imum temperature, and therefore loss of heat. 



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?8 T/ie Gas Engine 

the total efficiency is 0*37, and from that volume to v and atmos- 
pheric pressure, 0*14. The latter portion still obeys the same law 
as in a similar case of type 1 ; so that if the initial temperature at 
volume v be supposed 117 C. it will lose efficiency in a similar 
way. The temperature 90 1° C. will still exist at that point of the 
expanding line, so that it may be taken as similar to the case 
calculated on p. 75, where 1000 C. is the maximum. The loss 
of efficiency there is from 0*23 to o*i6 for an initial temperature 
of 1 1 7 C, which makes 0*14 become nearly 010. The total 
efficiency would therefore be 0*47 instead of 0-51 without previous 
heating. 

Efficiency diminishes with increased temperature of working 
fluid before compressing, if the expansion is carried to atmosphere, 
but does not change where the expansion is limited to the initial 
volume. 

Other causes of Loss. 

The third, fourth, and fifth causes of loss require for their ex- 
amination a comparison of the actual diagrams, and a knowledge 
of the phenomena of explosion and combustion, and so cannot be 
discussed at this stage. 



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79 



CHAPTER V. 

COMBUSTION AND EXPLOSION. 

In the preceding chapters the gas engine has been considered 
simply as a heat engine using air as its' working fluid ; it has been 
assumed that in the different cycles, the engineer is able to give 
the supply of heat either instantaneously, or slowly, at will ; and 
also that he can command temperatures so high as iooo° C. or 
1600 C. It is now necessary to study the properties of gaseous 
explosive mixtures in order to understand how far these assump- 
tions are true. 

On true Explosive Mixtures. 

When an inflammable gas is mixed with oxygen gas in certain 
proportions, the mixture is found to be explosive : a flame ap- 
proached to even a small volume contained in a vessel open to the 
air will produce a sharp detonation. Variation of the proportions 
will cause change in the sharpness of the explosion. There is a 
point where the mixture is most explosive ; at that point the in- 
flammable gas and the oxygen are present in the quantities 
requisite for complete combination. After explosion the vessel 
will contain the product or products of combustion only, no 
inflammable gas remaining unconsumed, or oxygen uncombined, 
both having quite disappeared in forming new chemical com- 
pounds. 

That mixture may be called the true explosive mixture. 

Definition, — When an inflammable gas is mixed with oxygen 
in the proportion required for the complete combination of both 
gases, the mixture formed is the true explosive mixture. 

If the chemical formula of an inflammable gas is known, the 
volume of oxygen necessary for the true explosive mixture can 



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8o 



The Gas Engine 



be at once calculated. Elementary substances combine chemi- 
cally with each other in certain weights known as the atomic or 
combining weights: chemical symbols are always taken as repre- 
senting those weights of the elements indicated. In dealing with 
inflammable gases used in the gas engine it is convenient to 
remember the following symbols and weights : 



Element 


Symbol 


Combining weight 


Oxygen 

Hydrogen 

Nitrogen 

Carbon 

Sulphur 


O 
H 
N 
C 
S 


x6 

z 

*4 
12 
32 



In entering or leaving any compound the elements invariably 
enter or leave in weights proportional to those numbers or 
multiples of them. Thus hydrogen and oxygen combine with 
each other, forming water ; the formula of the compound is 
H a O, meaning that 18 parts by weight contain 16 parts of O and 
2 parts of H. Similarly when carbon combines with oxygen two 
compounds may be formed, according to the conditions, carbonic 
oxide or carbonic acid, formulae CO and C0 2 , the former containing 
in 28 parts by weight, 12 parts of carbon and 16 parts of oxygen ; 
the latter in 44 parts by weight containing 12 parts of carbon and 
32 parts of oxygen. 

The formula of a compound therefore not only indicates its 
nature qualitatively, but it also indicates its quantitative composition. 

H 2 6 not only tells the nature of water, but it represents 18 
parts by weight ; CO means 28 parts by weight of carbonic oxide : 
C0 2 means 44 parts by weight of carbonic acid. The numbers 18, 
28 and 44 are know as the molecular weights of the three com- 
pounds in question. 

When dealing with gases it is more convenient to think in 
volumes than in weights. It is easier, for instance, to measure the 
proportions of explosive mixtures by volume and to say this mix- 
ture contains one cubic inch, one cubic foot or one volume of 
inflammable gas to so many cubic inches, feet or volumes of oxygen. 

Fortunately there exists a simple relationship between the 
volumes of elementary gases and their combining weights, and 



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Combustion and Explosion 8 1 

also between the volumes of compounds and their molecular 
weights. 

If equal volumes of the elementary gases are weighed, under 
similar conditions of temperature and pressure, it is found that 
their weights are proportional to the combining weights. Taking 
the weight of the hydrogen as i, then the weights of equal 
volumes of nitrogen and oxygen are 14 and 16 respectively. If 
then it is wished to make a mixture of hydrogen and oxygen gases 
in the proportion of 2 parts by weight of the former to 16 parts by 
weight of the latter, it is only necessary to take 2 vols. H and 

1 vol. O. The law may be stated in two ways, as follows : 

Taking hydrogen as unity the specific gravity of the elementary 
gases is the same as their combining weights ; or 

The combining volumes of the elementary gases are equal. 

Instead of troubling to weigh out portions of the gases it is 
at once known that one volume of nitrogen wt ighs 14 parts, the 
same volume of hydrogen weighing one part, oxygen 16 parts, and 
so on through all the gaseous elements, under the same tempera- 
tures and pressures. 

Knowing that water is the compound formed by the combus- 
tion of hydrogen and oxygen, and that its formula is H 2 0, it is at 
once apparent that the true explosive mixture of these gases is 

2 vols. H and 1 vol. O. By experiment it is found that the volume 
of the water produced is less (of course in the gaseous state) than 
the volume of the mixed gases before combination. 

The measurement requires to be made at a temperature high 
enough to keep the steam formed in the gaseous state. Measure 
2 vols. H and 1 vol. O into a strong glass vessel heated to 130 C ; 
the total is 3 vols. ; fire by the electric spark over mercury. It 
will be found that the steam formed when it has cooled to 130 C 
after the explosion, measures 2 vols. It has been found to be 
true for all gaseous compounds, that however many volumes of 
elementary gases combine to form them the product is always two 
volumes. In elementary gases, one volume always contains the 
combining weight ; in compound gases, two volumes always con- 
tain the molecular weight. Compared with hydrogen, therefore, 
the specific gravity of a gaseous compound is always one-half of 
the molecular weight. 

G 



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82 Tlie Gas Engine 

As before, the law may be stated in two ways : 

Taking hydrogen as unity, the specific gravity of a compound 
gas is half its molecular weight ; or 

The combining volume of a compound gas is always equal to 
double that of an elementary gas. 

These laws are known as Gay-Lussac's laws, and form part of 
the very basis of modern chemistry. 

Using them, the true explosive mixtures by volume and the 
volumes of the products of the combination can be found for any 
gas or mixture of gases, whether elementary or compound. 

The inflammable compound gases, used in the gas engine, 
forming some of the constituents of coal gas are : 



Inflammable gas 



Marsh gas 



Ethylene 
xbonic 



Formula 



CH 4 
I Carbonic oxide . CO 



Molecular weight Molecular vol. | 



16 2 

28 I 2 

28 2 



H,0 

Sicam. 

2 vols. 


CO, 

Carbonic 
acid. 


4 vols. 


2 VOls. 


4 vols. 


4 vols. 


— 


2 Vols. 


8 vols. 


8 vols. 



Applying Gay-Lussac's laws, the oxygen required for true 
explosive mixtures and the volumes of the products of combus- 
tion are as follows for all the inflammable gases used in the gas 
engine : 

2 vols, hydrogen (H) require 1 vol oxygen .(O) forming . 
2 vols, marsh gas (CH 4 ) require 4 vols, oxygen (O) forming . 
2 vols, ethylene (C 5 H 4 ) require 6 vols, oxygen (O) forming , 
2 vols, carbonic oxide (CO) require 1 vol. oxygen (O) forming 
2 vols, tetrylene (C 4 H 8 ) require 12 vols, oxygen (O) forming . 

With hydrogen and oxygen 3 volumes before combination 
become 2 volumes after combination. CH 4 and O, also C 2 H 4 and 
O, the volumes of the products of combustion, are equal to the 
volumes of mixture. With carbonic oxide and oxygen 3 volumes 
before become 2 volumes after combination. 

On Inflammability. 

Previous to 181 7, Sir Humphry Davy made the admirable 
researches which led him to the invention of the safety lamp. He 
then made experiments upon different explosive mixtures, and 
found that under certain conditions they lost the capability of 



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Combustion and Explosion 83 

ignition by the electric spark. True explosive mixtures, he ob- 
served, may lose inflammability in two ways ; by the addition of 
excess of either ot the gases or of any inert gas such as nitrogen, 
and by rarefaction. The hydrogen explosive mixture, if reduced to 
one-eighteenth of ordinary atmospheric pressure, cannot be in- 
flamed by the spark. Heated to dull redness at this pressure it 
will recover its inflammability and the spark will cause combination. 

One volume of the mixture to which has been added nine 
volumes of oxygen is uninflammable, but if the density is increased 
or the temperature raised, it recovers its inflammability. 

Eight volumes of hydrogen added, produces the same effect as 
the nine volumes of oxygen, but only one volume of marsh gas 
or half a volume of ethylene is required The excess which destroys 
inflammability varies with the temperature, increasing with increase 
of temperature. Heating the mixture widens the range, both of 
dilution with excess or inert gas and reduction of pressure. 

The point where inflammability ceases by diluting is very 
abrupt and sharply defined. The author has found that a coal 
gas which will inflame by the spark in a mixture of 1 gas and 
14 air will not inflame with 15 of air. If the experiment be re- 
peated on a warmer day it may inflame with 15 of air, but will not 
with 16 air. As the proportion is fixed for any given temperature 
it will be convenient to call that proportion for any mixture the 
i critical proportion/ Any mixture in the critical proportion be- 
comes inflammable by a very small increase of temperature or 
pressure. The exact limits of dilution temperature and pressure 
have yet to be discovered 

Passing from any true explosive mixture by dilution to the 
mixture in the critical proportion, the inflammability slowly 
diminishes, the explosion becoming less and less violent, till at last 
no report whatever is produced, and the progress of the flame (if 
a glass tube is used) is easily followed by the eye. 

In his great work on gas analysis, Professor Bunsen confirms 
Davy's observations in every particular, proving loss of inflam- 
mability by dilution and reduction of pressure as well as its 
restoration by heating, increase of pressure and slight addition of 
the inflammable gas. His work, however, was not published till 

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84 The Gas Engine 



On the Rate of Flame-Propagation. 

The sharp explosion of a true explosive mixture is due to the 
very rapid rate at which a flame, initiated at one point, travels 
through the entire mass and thereby causes the maximum pressure 
to be rapidly attained. With a diluted mixture the flame travels 
more slowly. Dilution therefore diminishes explosiveness in two 
ways— by increasing the time of getting the highest pressure and 
also by diminishing the highest pressure which can be got 
Professor Bunsen's experiments are the earliest attempts to 
measure the velocity of flame movement in explosive mixtures. 
His method is as follows : 

The explosive mixture is allowed to burn from a fine orifice of 
known diameter, and the rate of the current of the issuing gas 
carefully regulated by diminishing the pressure to the point at 
which the flame passes back through the orifice and inflames the 
explosive mixture below it This passing back of the flame occurs 
when the velocity with which the gaseous mixtures issue from the 
orifice is inappreciably less than the velocity with which the in- 
flammation of the upper layers of burning gas is propagated to the 
lower and unignited layers. Knowing then the volume of mixture 
passing through the orifice and its diameter, the rate of flow at 
the moment of back ignition is known. It is identical with the rate 
of flame propagation through the mixture. 

Bunsen made determinations for the true explosive mixtures 
of hydrogen and carbonic oxide. 

Velocity of Flame in true explosive Mixtures. {Bunsen.) 

Hydrogen mixture (2 vols. H and 1 vol. O). .34 metres per sec. 
Carbonic oxide mixture (1 vol. CO and 1 vol. O) . 1 metre per sec nearly. 

The method is a singularly simple and beautiful one and 
answered thoroughly for Professor Bunsen's purpose at the time 
he devised it. Several objections, however, may be brought against 
it. The mixture in issuing from the jet into the air as flame, 
becomes mixed to some extent with the air and so cools down ; 
the metal plate also, pierced with the orifice, exercises a great 
cooling effect. If the hole were made small enough the flame 
could not pass back at all, however much the flow is reduced, 



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Combustion and Explosion 8 5 

because the heat would be conducted away so rapidly as to 
extinguish the flame. This had been shown by Davy in 1817; 
indeed it is the principle of the safety lamp. These causes prob- 
ably make Bunsen's velocities too low. MM. Mallard and Le 
Chatelier have made velocity determinations by a method designed 
to obviate those sources of error. 

The explosive mixture is contained in a long tube of considerable 
diameter, closed at one end, open to the atmosphere at the other. 
At each end a short rubber tube terminates in a cylindrical space 
closed by a flexible diaphragm. A light style is fixed upon the 
diaphragms. A drum revolves close to each style, both drums 
upon the same shaft. A tuning fork, vibrating while the experi- 
ment is being made, traces a sinuous line upon the drum and so 
the rate of revolution is known. The mixture is ignited at the 
open end, and the flame in passing the lateral opening leading to 
the first diaphragm ignites the mixture there, and so moves the 
style and marks the drum; the arrival of the flame is signalled at 
the other end in the same way. The drums revolving together, 
the distance between the two style markings measured by the 
vibration marks of the tuning fork gives the time taken by the 
flame to move between the two points. The numbers got in this 
way are the rates of the communication of the flame through the 
mixture, back into the tube, while the flame can freely expand to the 
air; when both ends are closed the velocity is much greater. Then, 
not only does the flame spread from particle to particle of the 
explosive mixture at the rate due to contact of the inflamed particles 
with the uninflamedones, but the expansion produced by the inflam- 
mation projects the flame mechanically into the other part and so 
produces an ignition, which does not travel at a uniform rate, but at a 
continually accelerating one. In the same way, using the open tube 
but firing at the closed end, the expansion of the first portion adds 
to the apparent velocity of propagation, and projects the last 
portion of the mixture into the atmosphere. The true velocity of 
the propagation is the rate at which the flame proceeds from particle 
of inflamed mixture to uninflamed particle by simple contact ; the 
true velocity depends upon inflammability alone, the rate under 
other conditions depends also upon heat evolved, and therefore 
movement due to expansion, mechanical disturbance of the uni? 



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86 Tfie Gas Engine 

nited by the projection of the ignited portion into its midst. These 
conditions may vary much ; the inflammability remains constant 
Mallard and Le Chatelier's results for the true velocity of pro- 
pagations are : 

Velocity of Flame in true explosive Mixtures. 
{Mallard and U CkaUlUr.) 

per sec. 
Hydrogen mixture (a vols. H and i vol. O) . ao metres. 

Carbonic oxide (a vols. CO and i voL O) . . a*a „ 

Bunsen's rate for hydrogen mixture seems to have been too 
great, and for carbonic oxide mixture too little. The rate for a true 
and very explosive mixture such as hydrogen is liable to be inac- 
curately determined, as temperature variation makes a great 
change, and it is difficult even with Mallard and Le Chatelier's 
method to obtain concordant experiments. With less inflammable 
mixtures the difficulty disappears. As true explosive mixtures are 
never used in the gas engine, their properties concern the engineer 
only as a preliminary to the study of diluted mixtures. The most 
explosive mixture which can be made with air contains a large 
volume of nitrogen inevitably present as diluent. 

The following are some of their results with diluted mixtures, 
which are stated to be correct within 10 per cent, error of experi- 
ment : 
Velocity of Flame in diluted Mixtures. {Mallard and Le Chatelicr.) 

per sec. 
x vol. hydrogen mixture + $ vol oxygen . .17*3 metres. 

,, ,, +1 voL oxygen . .10 ,, 

,, + i vol. hydrogen ... 18 ,, 

,, ,, + i vol. hydrogen . .1119 

,, ,, + a vols, hydrogen . 8*i 

These rates show that the true explosive mixture of hydrogen 
and oxygen when diluted with its own volume of oxygen falls from 
20 metres per second to 10 metres, that is, it becomes one-half 
as inflammable ; when its own volume of hydrogen is the diluent, 
the velocity only falls to 11*9 metres per second. Hydrogen there- 
fore has less effect in diminishing inflammability than oxygen. 

Remembering the fact that the atmosphere contains one fifth 
of its volume of oxygen, the remaining four-fifths being nearly all 
nitrogen, it is easy to get the proportions for the strongest explosive 



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Combustion and Explosion 87 

mixture possible with air. Two volumes hydrogen require 1 volume 
oxygen, and therefore 5 volumes air. The strongest possible mixture 
with air is two-sevenths hydrogen, five-sevenths air. The following 
experiments are for hydrogen and air in different proportions : 
Velocity of Flame in diluted Mixtures. {Mallard and Le ChaUlUr.) 

Mixture, 1 vol. H and 4 vols, air 

„ 1 „ H and 3 vols, air 

„ 1 „ H and 2^ vols, air 

,, 1 ,, H and 1$ vols, air 

1 ,, H and i£ vols, air 

,, 1 ,, H and x vol air 

,, 1 „ H and £ vol. air 

Very strangely the velocity is greatest when there is an excess of 
hydrogen present. To get just enough of oxygen for complete burn- 
ing, 1 volume H requires i\ volumes air, which would be naturally 
supposed to be the most inflammable mixture, as it gives out the 
greatest heat, but for some reason it is not. When the hydrogen 
is increased beyond 1 volume H to \\ volumes air the velocity 
again falls off. A determination for coal gas and air gave 1 volume 
gas, 5 volumes air a velocity of roi metres per second, and 
1 volume gas, 6 volumes air 0*285 metres per second. With coal 
gas also the maximum velocity is got with the gas slightly in excess. 

So far, these rates of ignition or inflammation are measures of 
inflammability, and are the rates for constant pressure; the rates for 
constant volume are very different, and the problem is a more 
complex one. Inflaming at the closed end of the tube, they found 
that even very dilute mixtures gave a sharp explosion, and in the 
case of hydrogen true explosive mixture, the velocity became 1000 
metres per second instead of 20. With hydrogen and air 300 
metres per second were obtained. 

MM. Berthelot and Vieille have proved that under certain con- 
ditions even greater velocities than these are possible. The con- 
ditions, however, are abnormal, and the generation of M, Berthelot's 
explosive wave is exceedingly undesirable in a gas engine. It is 
generated by inflaming a considerable portion of the mixture at 
once, and so causing the transmission of a shock from molecule 
to molecule of the uninflamed mixture: this shock causes an 
ignition velocity nearly as rapid as the actual mean velocity of 
movement of the gaseous molecules at the high temperatures of 



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88 T/te Gas Engine 

combustion. The difference between this almost instantaneous 
detonation and the ordinary flame propagation may be compared 
to similar differences in the explosion of gun cotton discovered 
by Sir Frederic Abel. Gun cotton lying loosely, and open to the 
air, will burn harmlessly if ignited by a flame; indeed, a consider- 
able portion may be laid upon the open hand and ignited by a 
flame without the smallest danger. The same quantity in the 
same position, if fired by a percussive detonator, will occasion 
the most violent explosion, the nature of the shock given to the 
gun cotton by the detonator causing a transmission of the kind of 
vibration necessary to cause its almost instantaneous resolution 
into its component gases. 

The explosive wave in gases seems to originate in like con- 
ditions. Its velocity for the true explosive mixture of hydrogen 
and oxygen is 2841 metres per second, and for carbonic oxide 
mixture, 1089 metres per second The velocity is independent of 
pressure between half an atmosphere and one and a half atmo- 
sphere. It is independent, too, of the diameter of the tube used, 
within considerable limits, or of the material of the tube, rubber 
and lead tubes giving similar results. Diluting the mixtures di- 
minishes, and heating increases it. The experiments are very 
interesting and important, from a physicist's standpoint, but, 
fortunately for the inventor dealing with gas engines, the explosive 
wave is not easily generated in a gas engine cylinder; if it were, 
it would be impossible to run the engines without shock and 
hammering. 

The velocity which really concerns the engineer is that due 
to inflammability, and expansion produced by inflaming — the 
velocity, in fact, with which the inflammation spreads through a 
closed vessel. As it cannot be discussed without considering 
other matters — heat evolved by combustion, and temperatures and 
pressures produced — it will be advisable first to give the heat 
evolved by combustion, and then devote a complete chapter to 
explosion in a closed vessel. 

Heat evolved by Combustion. 

Careful experiments upon the heat evolved by the combustion 
of gases in oxygen have been made by Favre and Silberman, and 



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Combustion and Explosion 89 

also by Professor Andrews. The physicists first named burned 
the gases at constant pressure in a specially devised calorimeter. 
Professor Andrews mixed the gases in a thin spherical copper 
vessel, closed it, and exploded by the spark: the vessel being sur- 
rounded by water gave up its heat to the water, the weight of which 
being known, the rise of temperature gave the heat evolved. 

Quantities of heat are measured by taking water as the unit 
In this work, a heat unit always means the amount of heat neces- 
sary to raise unit weight of water through i°C. 

Taking an average of Favre and Silberman and Andrews's 
results, the inflammable gases used in gas engines evolve upon com- 
plete combustion the following amounts of heat : 

Heat units. 
Unit weight of hydrogen completely burned to H a O evolves . . 34.170 
Unit weight of carbon completely burned to CO a evolves . 8,000 

Unit weight of carbonic oxide completely burned to C0 2 evolves . 2,400 
Unit weight of marsh gas completely burned to CO^ and HoO evolves 13,080 
Unit weight of ethylene completely burned to CO a and H 2 evolves 11,900 

That is, one pound weight of hydrogen burned completely to 
water will evolve as much heat as would raise 34,170 lbs. of water 
through i° C, or the converse. One pound of carbon in burning 
to carbonic acid evolves as much heat as would raise 8,000 lbs. of 
water through i°C These numbers give the amount or quantity 
of heat evolved The intensity or temperature of the combustion 
may be calculated on the assumption that the whole heat is evolved 
under such conditions that no heat is lost, or is applied to any- 
thing else but the products of combustion. To make the calcu- 
lation it is necessary to know the specific heat of the products. 

The amount of heat required to heat unit weight of water 
through one degree is 1 heat unit, the specific heat of any other 
body is the number of heat units required to heat unit weight of the 
body through one degree. Gases have two different specific heats 
depending upon whether heat is applied while the gas is kept at con- 
stant volume, or at constant pressure; both are required in dealing 
with gas engine problems. The specific heat at constant volume 
is sometimes known as the true specific heat; in taking the specific 
heat at constant pressure the gas necessarily expands, and so does 
work on the external air; this specific heat is therefore greater 
than the former by the amount of work done. For the gases used 



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90 



The Gas Engine 



in the gas engine the two values are as follows. The ratio be- 
tween the two is also given, as it is frequently required in efficiency 
calculations. The experimental numbers are Regnault's, the 
calculated specific heat at constant volume, Clausius. 

Specific Heats of Gases. 
(For equal weights* Water = i.) 



Name of gas 



Air 

Oxygen 
Nitrogen 
Hydrogen 
Marsh gas 
Ethylene 
Carbonic oxide 
Steam . 
Carbonic acid 



Sp. heat at 


Sp. heat at 


Sp. heat con. pres. 


constant pressure 


constant volume 


Sp. heat con. vol. 


0*237 


0168 


1*413 


0*217 


o-i55 


1 403 


0244 


0173 


1*409 


3 "409 


2*406 


1*417 


o*593 


0467 


— 


0-404 


0*332 


1*144 


0-245 


0*173 


1*416 


0*480 


0369 


1*302 


0*216 


0*171 


1*165 



It is convenient to remember that the specific heats of com- 
bining or atomic weights of the elements are equal — Dulong and 
Petit's law. To this law there are few exceptions, and the per- 
manent elementary gases, oxygen, nitrogen, and hydrogen, obey it 
almost absolutely. As equal volumes of these gases represent the 
combining weights, it follows that equal volumes of these gases 
have the same specific heat Taking the specific heat of air as 
the unit, the specific heat of hydrogen and oxygen gases is also 
unity. The compound gases do not obey the law so closely. 
The calculation of temperature of combustion can now be made. 
The amount of heat evolved from unit weight of a combustible i? 
usually said to measure its calorific power, that amount divided by 
the specific heat of the products of the combustion is said to be the 
measure of its calorific intensity. The calorific intensity is indeed 
the theoretical temperature of the combustion : taking hydrogen 
first, unit weight evolves 34,170 heat units. But the water formed 
weighs 9 units (from formula H 2 0), and if its specific heat in the 
gaseous state were unity, the supposed maximum temperature of 

combustion would be 34 1 ? = 37966. But the specific heat is 



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Combustion and Explosion 91 

less than unity ; therefore the theoretical maximum will be greater. 

It is — 3417° = 79097. For certain reasons to be considered 
9 x 0*480 y * 

later, no such enormous temperatures are ever attained by com- 
bustion. In the above calculation the latent heat of steam should 
first have been deducted, as it is included in the total heat evolved 
as measured by the calorimeter : it is 537 heat units. 34,1 70 — 537 
gives the total heat available for increasing the temperature, the 

amended calculation is 34 I 7° "" . 537 =7 785 -4, still an exceedingly 
9 x 0*480 

high temperature. 

Calculating the heat evolved by burning carbon in the same 

way, but omitting any deduction for the latent heat of carbonic 

acid (it does not affect the calorimeter, as it does not condense), 

the theoretical temperature produced by burning in oxygen is 

still higher, being 10,174° C. Burning in air the theoretical 

temperatures are lower as the nitrogen present acts as a diluent, 

and must necessarily be heated to the same temperature as the 

products of the combustion. They are given as follows in ' Watts' 

Dictionary.' 

Temperature produced 

Calorific power ^ ■— - N 

In oxygen In air 
Carbon .... 8080 10174 C. 2710 C. 

Hydrogen .... 34462 6930° C. 274 1° C. 

These are the supposed temperatures burning in the open 
atmosphere, and therefore at constant pressure, the gases expand- 
ing doing work upon the air. At constant volume, that is, 
burning in a closed vessel so that the volume cannot increase but 
only the pressure, the temperature should be greater as the 
specific heat at constant volume is less. Allowing for that, the 
numbers become 

Theoretical Temps, of Combustion at Constant Volume. 

Temperature produced 

In oxygen In air 
Carbon .... 12820 — 

Hydrogen .... 9010 41 19 

Such temperatures have never been produced by combustion, 



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92 The Gas Engine 

for many reasons, of which all save the most potent have been 
discussed by the earlier writers on heat This is Dissociation. 



Dissociation. 

Most chemical combinations, while in the act of formation 
from their constituent elements, evolve heat, and as a general 
rule, the greater the heat evolved the more stable is the com- 
pound formed. The compound after formation may generally be 
decomposed by heating to a high enough temperature, heat being 
one of the most powerful splitting up agencies known to the chemist 
The nature of the decomposition varies with the compound. In 
many cases the process is irreversible, that is, although heating up 
will cause decomposition, cooling down again, however slowly, 
will not cause recombination. In some compounds, however, under 
certain conditions the process is reversible, and recombination 
occurs on slow cooling. 

Definition.— Dissociation may be defined as a chemical 
decomposition by the agency of heat, occurring under such con- 
ditions that upon lowering the temperature the constituents 
recombine. 

Groves found long ago that water begins to split up into 
oxygen and hydrogen gases at temperatures low compared to that 
produced by combustion. Deville made a careful study of the 
phenomena, and found that decomposition commences at 960 to 
1000 C. and proceeds to a limited extent : raising the temperature 
to 1200 C. increases it, but a limit is reached The amount of 
decomposition depending upon the temperature, for each tempe- 
rature there is a certain proportion between the amount of steam 
and the amount of free oxygen and hydrogen gases present If 
the temperature is increased, the proportion of free gases also 
increases : if temperature is diminished, the proportion of free 
gases diminishes. If the temperature be raised beyond a certain 
intensity, the water is completely decomposed : if lowered beyond 
a certain temperature, complete combination results. The same 
thing happens with carbonic acid, the temperature of decomposition 
is lower. 

It is quite evident, then, that at the highest temperatures pro- 



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Combustion and Explosion 93 

duced by combustion, the product cannot exist in the state of 
complete combination. It will be mixed to a certain extent with 
the free constituents which cannot combine further until the tem- 
perature falls; as the temperature falls, combustion will continue 
till all the free gases are combined. The subject, from its nature, 
is a difficult one in experiment, and accordingly different observers 
do not quite agree upon temperatures and percentages of dissocia- 
tion, but all are agreed that dissociation places a rigid barrier in 
the way of combustion at high temperatures, and prevents the 
attainment of temperatures, by combustion, which are otherwise 
quite possible. With no dissociation, hydrogen burning in oxygen 
should be able under favourable circumstances to give a tempera- 
ture of over 6000 C, as has been shown. Deville's experiments 
upon the temperature of the oxyhydrogen flame, at constant 
pressure of the atmosphere, gave under 2500 C. The estimate 
was made by melting platinum in a lime crucible, with the oxy- 
hydrogen flame playing upon the platinum, the crucible being 
well protected against loss of heat by lime blocks, so that the 
platinum could really attain the temperature of the flame; when 
at the highest temperature, the molten platinum was rapidly 
poured into a weighed calorimeter, and the rise in temperature 
noted. From this was calculated the temperature of the platinum. 
The experiment was dangerous and inaccurate, but it is the only 
serious attempt which has been made to determine the temperature 
of the oxyhydrogen flame at constant pressure. 

The highest temperature produced by hydrogen burning in 
oxygen has been determined by Bunsen, and also Mallard and 
Le Chatelier, for combustion at constant volume, that is, ex- 
plosion. 

As the theoretic calculation shows, with no dissociation a 
temperature of 9000 C. is possible. The highest maximum it 
is possible to assume from Bunsen's experiments is 3800 C. ; 
from Mallard and Le Chatelier's, 3500 C. The two sets of ex- 
periments are concordant. It is true the latter physicists do not 
attribute the difference wholly to dissociation, but they agree that 
part is due to this cause; and that there is an enormous difference 
between heat temperature actually got and that which should be 
possible if no limit existed all are agreed. With air, Bunsen's 



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94 The Gas Engine 

figures show a maximum of about 2000 C, Mallard and Le 
Chatelier say 1830 C; the present writer has also made experi- 
ments with hydrogen in air, and finds the highest possible tem- 
perature to be 1900 C The calculated maximum is 41 19 C. 
The difference is not so great as with the true explosive mixture, 
which is to be expected, but all experiments agree in proving that 
there is a considerable difference. 



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95 



CHAPTER VI. 

EXPLOSION IN A CLOSED VESSEL. 

The value of any inflammable gas for the production of power 
by explosion, can be determined apart altogether from theoretical 
considerations by direct experiment. It is evident that the gas 
which for a given volume causes the greatest increase in pressure, 
will give the greatest power for every cubic foot used, provided 
that the pressure does not fall so suddenly that it is gone before it 
can be utilised by the piston. 

Two qualities will be possessed by the best explosive mixture : 
(i) greatest pressure per unit volume of gas: (2) longest time of 
maximum pressure when exposed to cooling. 

In the gas engine itself the conditions are so complex that the 
problem is best studied in the first instance under simplified con- 
ditions. The author has made a set of experiments upon many 
samples of coal gas mixed with air in varying proportions, to find 
the pressures produced, and the duration of those pressures; 
igniting mixtures at atmospheric pressures and temperature, and 
also at higher temperature and initial pressures. He has made 
some experiments upon pure hydrogen and air mixtures in the 
same apparatus for comparison. 

The experimental apparatus is shown at fig. 19. It consists of 
a closed cylindrical vessel 7 inches diameter and 8| inches long, 
internal measurement, and therefore of 317 cubic inches capacity. 
It is truly bored, and the end covers turned so that the internal 
surface is similar to that of an engine cylinder ; the covers are 
bolted strongly so as to withstand high pressures. Upon the 
upper cover is placed a Richards indicator, in which the reci- 
procating drum has been replaced by a revolving one; the rate of re- 
volution is adjusted by asmall fan, a weight and gear giving the power. 



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96 



The Gas Engine 



The cylinder is filled with the explosive mixture to be tested; 
the drum is set revolving, the pencil of the indicator pressed 
gently against it, and the electric spark is passed between the 
points placed at the bottom of the space. The drum is enamelled 
and the pencil is a black-lead one. The pressure of the explo- 




WP6MT 



Fig. 19. — Clerk Explosion Apparatus. 

tion acts upon the indicator piston, and a line is traced upon the 
drum, which shows the rise and fall of pressure. The rising line 
traces the progress of the explosion ; the falling line the progress 
of the loss of pressure by cooling. The rate of the revolution of 
the drum being known, the interval of time elapsing between any 
two points of the explosion or cooling curve is also known. That 
is, the curve shows the maximum pressure attained, the time of 
attaining it, and the time of cooling. Line b on fig. 20 is a fac- 



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Explosion in a Closed Vessel 



9? 



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simile of the curve produced by the explosion of a mixture con- 
taining i vol. hydrogen and 4 vols. air. Each revolution of the 
drum was accomplished in 0*33 sec, so that each tenth of a revolu- 
tion takes 0*033 sec - The vertical 
divisions give time; the horizontal, 
pressures. In this experiment the 
maximum pressure produced by the 
explosion is 68 lbs. per square inch 
above atmosphere, and it is attained 
in 0*026 second. Compared with 
the rate of increase the subsequent 
fall is very slow. The rise occurs in 
0*026 second; the fall to atmo- 
sphere again takes 1*5 second, or 
nearly sixty times the other. It is 
in fact an indicator diagram from an 
explosion where the volume is con- 
stant, the motor piston being absent, 
and the only cause of loss of pres- 
sure is cooling by the enclosing 
walls. The exact composition of 
the mixture, its uniform admixture, 
the temperature and pressure before 
ignition, are all accurately known. 
After studying explosions under 
these known conditions, it becomes 
easier to understand what occurs 
under more complex conditions, 
where the moving piston makes the 
cooling surface change, and where the 
expansion doing work also requires 
consideration. As the rapidity 
of the increase of pressure measures 
the explosiveness of a mixture, the 
time occupied from the commence- 
ment of increase to maximum pres- 
sure will be called the time of explosion. The explosion. is com- 
plete when maximum pressure is attained. It does not follow from 

H 



X 



a. 
x 

W 



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9 8 



The Gas Engine 




tpuj 



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•ajaijdsouire aAOqu 
•bs aad 'sqj uj ajnssajj 



•OJOqcf^OUJlV! J>.\Oqt! 

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Explosion in a Closed Vessel 



99 



this that the combustion is complete; that is another matter. The 
explosion arises from the rapid spreading of the flame throughout the 
whole mass of the mixture, which may be called the inflammation of 
the mixture. More or less rapid inflammation means more or 
less explosive effect, but not complete combustion. The complete 
burning of the gases present does not occur till long after com- 
plete inflammation. 

The terms combustion^ explosion \ and inflammation will be used 
in this sense alone : 

Combustion, burning ; complete combustion, the complete 
burning of the carbon of the combustible gas to carbonic acid, and 
the hydrogen to water. So long as any portion of the combustible 
remains uncombined with oxygen the combustion is incomplete. 

Complete explosion, the attainment of maximum pressure. 

Time of explosion; the time elapsing between beginning of 
increase and maximum pressure. 

Complete inflammation, the complete spreading of the flame 
throughout the mass of the mixture. 

Confusion has arisen through the indifferent use of these terms, 
which are really distinct and are not synonymous. 

With mixtures made with Glasgow coal gas the author has 
obtained the following maximum pressures and times of explosion. 

Explosion in a Closed Vessel. [Clerk.) 
Mixtures of air and Glasgow coal gas. 

Temp, before explosion i8° C. 

Pressure before explosion atmospheric. 





Mixture 




Gas. 






Air. 


I VOL 






13 vols. 


I vol. 






11 vols. 


I vol. 






9 vols. 


i vol. 






7 vols. 


i vol. 






5 vols. 



Max. press, above atmos. 
in pounds per sq. in. 




Time of explosion 


o'28 


sec. 


018 


sec. 


013 


sec. 


007 


sec. 


0*05 


sec. 



The highest pressure which any mixture 01 coal gas and air 
is capable of producing without compression is only 96 lbs. per 
sq. in. above atmosphere and the most rapid increase is not more 
rapid than always occurs in a steam cylinder at admission. Many 



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IOO 



The Gas Engine 



are still prejudiced against gas, compared with steam, because of 
the so-called explosive effect, and the fear that gas explosions 
may occasion pressures quite beyond control, like solid explosives. 
The fear is quite unfounded ; the pressure produced by the 
strongest possible mixture of coal gas and air is strictly limited 
by the pressure before ignition,and can always be accurately known; 
and so provided for by a proper margin of safety in the cylinders 
and other parts subject to it. 

The most dilute mixture of air and Glasgow gas which can be 
ignited at atmospheric pressure and temperature contains T ^ of 
its volume of gas, and the pressure produced is 52 lbs. above 
atmosphere. The time of explosion is 0*28 second; so slow is 
the rise that it cannot with justice be termed an explosion. It is 
too slow to be of any use in an engine running at any reasonable 
speed ; the stroke would be almost complete before the pressure 
had risen. The mixture containing £ of its volume of gas is that 
with just enough oxygen to burn the gas. It is anomalous that 
the highest pressure is given with excess of coal gas. The rate of 
ignition also is greatest with that mixture. This agrees with the 
results obtained by Mallard and Le Chatelier, excess of hydrogen 
giving the highest rate of inflammation. 

Similar experiments were made with air and Oldham coal gas. 

Explosion in a Closed Vessel. {Clerk.) 

Mixtures of air and Oldham coal gas. 

Temp, before explosion 17 C. 

Pressure before explosion atmospheric. 



Mixture 


Gas. 


Air. 


I vol. 


14 vols. 


1 vol. 


13 vols. 


1 vol. 


12 VOls. 


1 vol. 


11 vols. 


1 vol. 


9 vols. 


1 vol. 


7 vols. 


1 vol. 


6 vols. 


1 vol. 


5 vols. 


1 vol. 


4 vols. 



Max. press, above atmos. 
in pounds per sq. in. 



Time of explosion 



40 

51 '5 

60 

61 

78 

87 

90 

9i 
80 



0*45 sec. 
031 sec. 
024 sec. 
0*17 sec. 
o'o8 sec. 
006 sec. 
0*04 sec. 
0055 sec. 
o - i6 sec. 



The highest pressure in this case is 91 lbs. per square inch 



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Explosion in a Closed Vessel 



IOI 



above atmosphere, but the most rapid explosion is 0*04 second 
and 90 lbs. pressure, a little less pressure than is given by Glasgow 
gas but a slightly more rapid ignition. The mixtures are evidently 
more inflammable, as the critical mixture is T l y volume of gas 
instead of ^ as with Glasgow gas. Although repeatedly tried, 
a mixture of 1 volume gas 15 volumes air failed to inflame with 
the spark. 

Hydrogen and air mixtures were also tested as follows : 

Explosion in a Closed Vessel. {Clerk.) 

Mixtures of air and hydrogen. 

Temp, before explosion i6 Q C. 

Pressure before explosion atmospheric. 



Mixture 


Max. press, above atmos. 
in pounds per sq. in. 


Time of explosion 


Hyd. 
1 vol. 
1 vol. 
a vols. 


Air. 
6 vols. 

4 vols. 

5 vols. 


41 
68 
80 


0*15 sec. 
0*026 sec. 
o"oi sec. 



The inferiority of hydrogen to coal gas, volume for volume, is 
very evident ; the highest pressure is only 80 lbs. above atmosphere, 
and the mixture requires \ of its volume of hydrogen to give it, 
while coal gas gives the same pressure with about ^ volume. The 
hydrogen mixture, too, ignites so rapidly that it would occasion 
shock in practice, the strongest mixture having an explosion time 
of one-hundredth of a second. With gas the most rapid is four- 
hundredths of a second. 

The Best Mixture for use in non-compression Engines. 

From these tables can be ascertained the best gas and the best 
mixture for use in non-compression engines with cylinders kept 
cold. Take first Glasgow gas, and determine which mixture gives 
the best result. 

(1) Power of producing pressure. 

Suppose one cubic inch of Glasgow coal gas to be used in each of 
the five mixtures, whose maximum pressures and times of explo- 
sion are given in the table on p. 99, the mixtures would measure 



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102 The Gas Engine 

respectively 14, 12, 10, 8, and 6 cubic inches. Let them be placed 
in cylinders of 14, 12, 10, 8 and 6 square inches piston area ; the 
piston will in each case be raised one inch from the bottom of its 
cylinder. If the pressures upon the piston were the same, equal 
movements of piston would give equal power ; if therefore the 
mixtures gave equally good results the maximum pressure multiplied 
by the piston area will in all cases be the same. 

Multiplying 14, 12, 10, 8 and 6 by their corresponding pres- 
sures 52, 63, 69, 89, and 96 respectively, the products are 728, 
756, 690, 712, and 576. These numbers are the pressures in 
pounds which each mixture is capable of producing with one 
cubic inch of Glasgow coal gas, cylinders of such area being used 
that the depth of mixture is in every case one inch. 

Proportion of Glasgow gas in mixture fa, fa, fa, J, £. 
Pressure produced upon pistons by , 
one cubic inch . . > ' /0 *"" • a/ *~ 

The best mixture is seen at a glance ; it is that containing 
one-twelfth of gas. The pressure produced by one cubic inch of 
gas is at its highest value 756. pounds, in a cylinder of 12 inches 
piston area, and containing 1 2 cubic inches of mixture. 

' In modern gas engines the time taken by the piston to make 
the working part of its stroke is generally about one-fifth of a 
second. If the pressure in one mixture has fallen more, proportion- 
ally in that time, then although it may give the highest maximum, 
it may lose too rapidly to give the highest mean pressure. To find 
this cooling effect, find the pressure to which each mixture falls 
at the end of 0*2 second after maximum pressure ; it is in the 
different cases : 

Mixture containing gas . . . fa, fa, fa t \, *. 

Time after beginning explosion (o '2 » . Q _ - ^ me%m _.„„ r _ 

, & \ ; o 48, 038, o 33, 027, 0*25 sec. 

sec. after max. pressure) > 

Pressure in lbs. per sq. in . . . 43, 48, 47, 55, 57. 

Press, respectively by 14, 12, 10, 8, ) , , 

and 6 ' 57 47 °' ** 4 °' 342 ' 

The lower row expresses the relative pressures still remaining 
after allowing each explosion to cool for one- fifth of a second 
from complete explosion ; they express the resistance to cooling 
possessed by the mixtures. It is evident at once that the 



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Explosion in a Closed Vessel 103 

strongest mixtures cool most rapidly ; a higher temperature being 
produced, more of the heat of the explosion is lost in a given time. 

(2) Power of producing pressure and resisting cooling. 

To find the best mixture for producing pressure and resisting 
cooling, those numbers are to be added to the corresponding ones 
for maximum pressure : 

Proportion of Glasgow gas in mixture ^ fa, &, \, £. 
Pressure produced upon pistons by> ?2Q ^ ^ ?I2 ^ 

one cubic inch gas . > 

Pressure remaining upon pistons o'a { 6q2> 6 

sec. after complete explosion . J 
Mean pressure 665, 666, 580, 576, 459. 

The mean of the two sets gives numbers expressing the 
relative values of the mixture for producing pressure, and at the 
same time resisting cooling. The two weakest mixtures are best 
in both respects, the low result given by the strongest mixture is 
due to the fact that excess of gas is present and it remains unburned, 
it proves how easily the consumption of an engine may be increased 
by even a slight excess of gas in the mixture. 

The two best mixtures ignite too slowly, but in the actual 
engine that is easily controlled, as will be explained later. 
The best mixtures are 1 vol. gas 13 volumes air, and 1 voL 
gas 11 volumes air. With more gas the economy will rapidly 
diminish. 

The experiments with Oldham gas treated in the same way 
give the following results : 

Proportion of Oldham gas in \ \ 1 1 1 u 1 1 1 l 

mixture . . . . f ** *' * Ai *' *' *' *' * 
Pressure produced upon pistons > ^ ^ ^ ?Qo ^ ^ ^ 4QQ 

by one cubic inch gas . ' 

Pressure remaining upon pistons \ 

0-2 sec. after complete explo- !• 3*. 4o, 4 . 44. 44. 47. 5a. 5<>. 4& 

sion per sq. inch ' 

Pressure per piston . 4^5. 5&>, 54$. 528. 44©. 37*. 3*4. 3«>. 230. 

Mean pressure upon piston . . 53 2 » 64°' 66 3- 6 3<>. 610, 536, 497, 423. 3*5- 

Here, too, the best mixture lies between one-twelfth and one- 
fourteenth of gas ; with less and more gas the result becomes worse 
and worse. Glasgow and Oldham gases seem to be very nearly 
equal in value per cubic foot for the production of power, as the 



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104 The Gas Engine 

pressure produced from one cubic inch in the best mixture of 
each is very similar. The average pressures during 0*2 second 
from complete explosion are exceedingly close, Glasgow gas 
mixture containing one-twelfth gas giving 666 lbs. pressure per 
cubic inch of gas, and Oldham gas for the same mixture and the 
same quantity giving 630 lbs. : Glasgow gas one-fourteenth mixture 
665 lbs. pressure, Oldham gas 640 lbs. The hydrogen experiments 
give as follows : 

Proportion of hydrogen gas in mixture . \, \, } . 
Pressure produced upon pistons by one 1 2g 2go 

cubic inch hydrogen . . . .1 
Pressure remaining upon pistons 0*2 

sec. after complete explosion per sq. • 35, 39, 40. 

inch 

Pressure per piston . 245, 195, 140. 

Mean pressure upon piston . 266, 267, 210. 

The best mixture with 1 cubic inch of hydrogen only gives a 
pressure of 267 lbs. available for 0*2 second, so that its capacity 
for producing power, compared with Glasgow and Oldham gas, is 
as 267 is to 665 and 640 respectively. To produce equal power 
with Glasgow gas nearly two-and-a-half times its volume of hydrogen 
is required. The idea is very prevalent among inventors that if 
pure hydrogen and air could be used, greater power and economy 
would be obtained ; these experiments prove the fallacy of the 
notion. Hydrogen is the very worst gas which could be used in 
the cylinder of a gas engine, it is useful in conferring inflamma- 
bility upon dilute mixtures of other gases, but when present in 
large quantity in coal gas it diminishes its value per cubic foot for 
power. 

Pressures produced if no Loss or Suppression 
of Heat Existed. 

From the fact already mentioned in the last chapter, that the 
theoretical temperatures of combustion are never attained in 
reality, it will naturally be expected that the pressures produced 
by explosions in closed vessels will also fall short of theory. 
This is found to be the case. It has been observed by every 
experimenter upon the subject, beginning with Hirn in 1861, 
who determined the pressures produced by the explosion of coal 



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Explosion in a Closed Vessel 



105 



gas and air, and hydrogen and air. He used two explosion vessels 
of 3 and 36 litres capacity ; they were copper cylinders with dia- 
meters equal to their length. He used a Bourdon spring mano- 
meter to register the pressure. He states that : 

(1) With 10 per cent hydrogen introduced the results were : 
according to experiment, 3*25 atmospheres ; according to calcu- 
lation, 5 *8 atmospheres, ir* 9 7***^ 

(2) With 20 per cent, of hydrogen, the results were : according 
to experiment, 7 atmospheres^which is very much below the cal- 
culation. ^ — , 7%5" 

(3) With to per cent of lighting gas introduced the results 
were : according to experiment, 5 atmospheres, i.e. much more 
than with the introduction of an equal volume of pure hydrogen. 

He notices especially the low pressure produced by hydrogen 
as compared with lighting gases, but observes truly that this should 
not excite surprise— although the heat value of hydrogen is great, 
yet it is so when compared with equal weights of other substances — 
and that coal gas being four or five times as heavy as hydrogen, 
quantity is balanced against quality ; therefore volume for volume 
it gives out more heat. 

He considers that there is no difficulty in explaining the very 
considerable difference found between calculation and experiment, 
as the metal sides are at so low a temperature compared with the 
explosion, that the heat is rapidly conducted away, and the 
attainment of the highest temperature is impossible. Bunsen, in 
his experiments, observed the same difference, and so later did 
Mallard and Le Chatelier. The author's experiments fully 
confirm the accuracy of those observers. In no case, whether 
with weak or strong mixtures of coal gas and air, or hydrogen 
and air, is the pressure produced which should follow the com- 
plete evolution of heat. 

Thus, with hydrogen mixtures (Clerk's experiments) : 



tf.70 



& 





Per sq. in 




1 vol. H 6 vols, air gives by experiment 


41 lbs. 


above atmosphere. 


The calculated pressure is . 


• 88-3 


II IF 


1 vol. H 4 vols, air experiment gives . 


68 


■ ■ if 


Calculated pressure is . 


. 124 


11 >. 


2 vols. H 5 vols, air experiment gives 


80 


•• >* 


Calculated pressure is . 


. 176 


• > 



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106 Tke Gas Engine 

Without exception the actual pressure falls far short of the 
calculated pressure ; in some manner the heat is suppressed or 
lost That the difference cannot altogether be accounted for by 
loss of heat is easily proved ; the fall of pressure is so slow from 
the maximum that it is impossible that any considerable proportion 
of heat can be lost in the short time of explosion. If so large a 
proportion were lost on the rising curve, it could not fail to show 
upon the falling curve ; it would fall in fact as quickly as it rose. 
Again, the increase of pressure would be less in a small than in a 
large vessel, as the small vessel exposes the larger surface pro- 
portionally to the gas present. It is found that this is not so. 
Bunsen used a vessel of a few cubic centimetres capacity, and got 
with carbonic oxide and oxygen true explosive mixture 10*2 atmo- 
spheres maximum pressure ; Berthelot with a vessel 4000 cb. c 
capacity got io*i atmospheres ; with hydrogen true explosive 
mixture Bunsen 9*5 atmospheres, Berthelot, 9*9 atmospheres. All 
the difference, therefore, cannot be accounted for by loss before 
complete explosion. 

Mixtures of air and coal gas give similar results. 

The following are the observed and calculated pressures for 
Oldham coal gas. {Clerk's experiments.) 

Per sq. in. 
1 voL gas 14 vols, air, experiment gives 40 lbs. above atmosphere 

Calculated pressure is 89*5 ,, ,, 

1 vol. gas 13 vols, air, experiment gives 51*5 ,, ,, 

Calculated pressure is 96 , , , , 

1 vol. gas 12 vols, air, experiment gives .60 ,, ,, 

Calculated pressure is 103 „ ,, 

1 vol. gas 11 vols, air, experiment gives . .61 ,, ,, 

Calculated pressure is 112 ,, ,, 

1 vol. gas 9 vols, air, experiment gives -78 ,, ,, 

Calculated pressure is 134 ,, ,, 

1 vol. gas 7 vols, air, experiment gives 87 ,, ,, 

Calculated pressure is 168 ,, 

1 vol. gas 6 vols, air, experiment gives .90 ,, ,, 

Calculated pressure is 192 ,, ,, 

The results with Glasgow gas are so similar that it is unneces- 
sary to give a table ; in no case does the maximum pressure 
account for much more than one-half of the total heat pre- 
sent. As all of the deficit cannot have disappeared previous 
to complete explosion, it follows that the gases are still burning 
on the falling curve, that is, the' falling curve does not truly 



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Explosion in a Closed Vessel 107 

represent the rate of cooling of air heated to the maximum tem- 
perature, because heat is being continually added by the continued 
combustion of the mixture. This will be fully proved by a study 
of the curves. 

It may, however, be taken as completely proved by the 
complete accord of all physicists who have experimented on the 
subject, that for some reason nearly one-half of the heat present 
as inflammable gas in any explosive mixture, true or dilute, is 
kept back and prevented from causing the increase of pressure to 
be expected from k. Although differences of opinion exist on the 
cause, all are agreed on the fact ; they also agree in considering 
that inflammation is complete when the highest pressure is 
attained. 

Temperatures of Explosion. 

With a mass of any perfect gas confined in a closed vessel the 
absolute temperatures and pressures are always proportional ; double 
temperature means double pressure. Temperatures t, / (absolute), 

T P 

pressures corresponding v y p; then - = - (Charles's law). If ex- 
plosive mixtures behaved as perfect gases, the pressure before 
explosion and temperature being known, the pressure of ex- 
plosion at once gives the corresponding temperature. It has 
been shown at page 82 that explosive mixtures do not fulfil 
this condition, but change in volume from chemical causes 
quite apart from physical ones. It follows, therefore, that these 
changes must be known before the temperature of the explosion 
can be calculated from the pressure. In the cases of hydrogen 
and carbonic oxide true explosive mixtures with oxygen, a 
contraction of volume is the result of combination. It comes to 
the same thing as if a portion of the perfect gas in the closed 
vessel was lost during heating ; the temperature then could not 
be known at the higher pressure unless the volume lost is also 
known. 

Suppose one-third of the volume to disappear, upon cooling 
to the original temperature, the pressure would be reduced to 
two-thirds of the original pressure, and this fraction of the 
original pressure must be taken as / 1 =-io. As both steam and 



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108 T/ie Gas Engine 

carbonic acid at temperatures high enough to make them per- 
fectly gaseous occupy two-thirds of the volume of their free 
constituents, it follows that p x must be taken as § /, wherever 
the temperatures are such that combination is complete. But 
here another difficulty occurs. Bunsen found that hydrogen 
and oxygen in true explosive mixtures gave an explosion pressure 
of 9*5 atmospheres. The calculated pressure for complete combus- 
tion, and allowing for chemical contraction is 2 1 "3 atmospheres. It 
is evident enough that complete combustion has not occurred, but 
it is difficult to say what fraction remains uncombined Yet 
unless the fraction in combination be known the contraction cannot 
be known, and therefore the temperature corresponding to the 
pressure cannot be known. 

Berthelot has pointed out that in a case of this kind the true 
temperature cannot be calculated, but it may be shown to lie 
between two extreme assumptions, both of which are erroneous. 

(1) Temperature calculated on assumption of no contraction. 

(2) Temperature calculated on assumption of the complete 

contraction. 

Let the two temperatures be (1) t 1 and (2) t. 

T , T 

2 vols. H, 1 vol. O, explosion pressure) or . ofloo°C 

(absolute) 9-9 atmospheres . . » 

2 vols. CO. 1 vol. O, explosion pressure 1 2 6i2°C aimPC 

(absolute) 10 '8 atmospheres . i 

The lower temperature could only be true if no combination 
whatever had occurred, which is impossible, as then no heat at all 
could be evolved; the higher temperature could only be true if com- 
plete combination, and therefore complete contraction, occurred. 
The truth is somewhere between these numbers. 

When the explosive mixture is dilute, the limits of possible 
error are narrower, because the possible proportion of contraction 
is less ; with hydrogen and air mixture in proportion for complete 
combination, 2 volumes of hydrogen require 5 volumes of air. 
The greatest possible contraction of the 7 volumes is therefore 1 
volume. If all the hydrogen burned to steam, the 7 volumes 
contract to 6 volumes. With more dilute mixtures the pro- 
portion diminishes. 

With a mixture containing £ of its volume hydrogen, 10 



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Explosion in a Closed Vessel 



109 



volumes can only suffer contraction to 9 volumes. With \ volume 
hydrogen, 14 volumes can contract to 13 volumes. 

The limits of maximum temperatures for those mixtures are as 
follows {Clerk) : 



1 vol. H, 6 vols, air, explosion pressure \ • 
(absolute), 557 lbs. per sq. in. . . J" 

1 vol. H, 4 vols, air, explosion pressure ) 
(absolute), 82 7 lbs. per sq. in. . . f 

2 vols. H, 5 vols, air, explosion pressure » 

(absolute), 947 lbs. per sq. in. . . f 



T 1 
826°C. 

1358 c. 

161s 1 C. 



T 

909° C. 

1539° C 
I929°C. 



The possible error is here much less than with true explosive 
mixtures ; coal gas is of such a composition that some of its 
constituents expand upon decomposition previous to burning, and 
so to some extent balance the contraction produced by the 
burning of the others. The possible error is therefore still further 
reduced The composition of Manchester coal gas as determined 
by Bunsen and Roscoe is as below. The oxygen required for the 
complete combustion of each constituent is also given, and the 
volumes of products formed. 

Analysis of Manchester Coal Gas. (Bunsen and Roscoe.) 









vols. 


Hydrogen, H . , . 


45-58 


Marsh gas, CH 4 . 


349 


Carbonic oxide, CO . 


664 


Ethylene, CaH 4 . 


4*08 


Tetrylene, C 4 H« . 


2-38 


Sulphuretted hydrogen, H 2 S 


029 


Nitrogen, N 


2*46 


Carbonic acid, CO a . 


3'67 


Total .... 


100 00 



Amount required 
for complete 




Products 


combustion 




vols. 


vols. 


2279 


45-58, H,0 


6 9 '8 


1047, C0 2 & H^O 


3'3« 


6 04, CO a 


12*24 


1632, COa&H^O 


14-28 


1904, CO a & H 2 


0'43 


058, H 2 & SO» 




2 46 


— 


3'67 


12286 O 


19899, C0 2 H 2 0&S0 2 



When burned in oxygen 100 volumes of this sample of gas 
require 122*86 volumes of oxygen, total mixture 222*86 volumes; 
the products of the combustion measure 198 -99 volumes. Calcula- 
ting to percentage, 100 volumes of the mixture will contract to 89-4 



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no 



The Gas Engine 



volumes of the products. As ioo volumes ot the mixture will 
contain 55*1 volumes of oxygen, it follows that if air be used, four 
times that volume of nitrogen will be associated with it, that is, 
55*1 x 4 = 220*4. The strongest possible explosive mixture ot 
this coal gas with air containing 100 volumes of the true explosive 
mixture will be 320*4 volumes, and it will contract upon complete 
combustion to 309*8 volumes. 

One volume of this gas requires 6*14 volumes air for complete 
combustion, and too volumes of the mixture contract to 96*6 
volumes of products and diluent. A contraction of 3*4 per cent. 
Dilution still further diminishes the change ; thus a mixture, 1 
volume gas 13*28 volumes air, will have only half that contraction, 
or 1*7 per cent. 

From these figures it is evident that the limits of possible 
error in calculating temperature from pressure of explosion does 
not exceed, in the worst case, with coal gas and air 3*4 per cent., 
and in weaker mixtures half that number. The fact that the whole 
heat is not evolved at the explosion pressure, and that therefore 
the whole contraction does not occur then, further reduces the 
error. It is then nearly correct to calculate temperature from 
pressure without deduction for contraction. This has been done 
for Glasgow gas and for the Oldham gas experiments by the 
author. 

Explosion in a Closed Vessel. [Clerk.) 
A fixtures of air and Glasgow coal gas. 

Temp, before explosion 18 C. 

Pressure before explosion atmos. 147 lbs. 





Mi 


Gas. 




1 vol. 




1 vol. 




1 vol. 




1 vol. 




1 vol. 





Air. 

13 vols, 
ir vols. 

9 vols. 

7 vols. 

5 vols. 



Max. press, above atmos. 
in pounds per sq. in. 



52 
63 
69 
89 
9° 



Temp, of explosion 

calculated from 
observed pressure 



1047° C. 
i26v'C. 
1.^84 C. 
1780'C. 
1918 C 



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Explosion in a Closed Vessel 



in 



Mixtures of air and Oldham coal gas. 
Temp, before explosion 



i 7 ° C 





Max. press, above 


Temp, of explosion 


Theoretical temp, 
of explosion if all 


Mixture 


atmos. in pounds 


calculated from 




per sq. in. 


observed pressure 


heat were evolved 


Gas. I Air. 






i vol. 1 14 vols. 


40 


8o6°C. 


l 7 86°C. 


1 vol. 1 13 vols. 


51*5 


io33°C. 


1912° C. 


1 vol. 12 vols. 


60 


1202 C. 


2058° C. 


1 vol. | 11 vols. 


61 


1220 C. 


2228°C. 


1 vol. | 9 vols. 


78 


1557° C 


2670 C. 


1 vol. j 7 vols. 


87 


1733° C. 


3334° C. 


1 vol. 1 6 vols. 


90 


1792 c. 


3808 °C. 


1 vol. j s vols. 


9* 


1812 C. 




1 vol. j 4 vols. 


80 


1595° C. 





Those temperatures calculated from maximum pressure, 
although not quite true are very nearly so, whatever be the theory 
adopted to explain the great deficit of pressure. It does not follow, 
however, that they are the highest temperatures existing at the 
moment of explosion ; they are merely averages. The existence of 
such an intensely heated mass of gas in a cold cylinder causes 
intense currents, so that the portion in close contact with the 
cold walls will be colder than that existing at the centre. There 
will be a hot nucleus of considerably higher temperature than 
that outside, but whatever that temperature may be, the increase 
of pressure gives a true average. It may be taken, then, that 
coal gas mixtures with air give upon explosion temperatures 
ranging from 8oo° C. to nearly 2000 C, depending on the dilution 
of the mixture. The more dilute the mixture the lower the 
maximum temperature ; increase of gas increases maximum tempe- 
rature at the same time as it increases inflammability. 

The author has made explosion experiments in the same 
vessel with mixtures previously compressed, and finds that the 
pressures produced with any given mixture are proportional to 
the pressure before ignition, that is, with a mixture of constant 
composition, double the pressure before explosion, keeping tempe- 
rature constant at 18 C, doubles the pressure of explosion. The 
experiments are laborious, and they are not yet complete for pub- 
lication, but the general principles already developed are true for 
compressed mixtures also. 



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112 The Gas Engine 

Efficiency of Gas in Explosive Mixtures. 

Rankine defines available heat as follows : 

* The available heat of combustion of one pound of a given 
sort of fuel is that part of the total heat of combustion which is 
communicated to the body to heat which the fuel is burned ; 
and the efficiency of a given furnace, for a given sort of fuel, is the 
proportion which the available heat bears to the total heat/ 

The gas engine contains furnace and motor cylinder in one ; 
nevertheless the efficiency of the working fluid is quite as distinct 
from the furnace efficiency as in the steam engine. Rankine's de- 
finition is quite true for the gas engine. 

The fuel being gas, the working fluid consists of air and its fuel 
and their combinations ; the available heat is that part of the 
heat of combustion which serves to raise the temperature of the 
working fluid ; the part which flows into it to make up for loss to 
the cold cylinder walls cannot be considered available. To be 
truly available it must either increase temperature, or keep it 
from falling by expansion. The heat flowing through the 
cylinder walls is a furnace loss, incident to the explosion method 
of heating. 

The experiments upon explosion in a closed vessel provide 
data for determining the furnace efficiency as distinguished from 
that of the working fluid. The proportion of heat flowing from 
an explosion to the walls in unit time will depend upon the 
surface of the walls for any given volume. The smaller the 
cooling surface in proportion to volume of heated gases, the 
slower will be the rate of cooling. Therefore to be applicable to 
any engine, the explosion vessel in which the experiments are 
made should have the same capacity and surface as the explosion 
space of the engine. 

The author's experiments are therefore only strictly applicable 
to engines with cylinders similar to his explosion vessel. Within 
certain limits, however, the error introduced by applying them to 
other engines is inconsiderable. 

Assuming the stroke of a gas engine (after explosion) to take 
o-2 second, this may be taken as the time during which the 
pressure of explosion must last if it is to be utilised by the 



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Explosion i?i a Closed Vessel 113 

engine. In a closed vessel the pressure falls considerably in 0*2 
second, the average pressure may be taken as nearly indicating 
the available pressure during that time. The heat necessary to 
produce that pressure is the available heat ; and its proportion to 
the total heat which the gas present in the mixture can evolve is 
the efficiency of the gas in that explosive mixture. 

With Oldham gas the best mixture is (table, p. 103) 1 volume 
gas 12 volumes air ; the average pressure during the first fifth of 
a second is 51 lbs. per square inch above atmosphere. If all 
the heat present heated the air, the pressure should be 103 lbs. 
effective, so that the efficiency of the heating method is -^ =■ 
0-49. 

The strongest mixture which still contains oxygen in excess 
is 1 volume gas 7 volumes air, the average available pressure is 
67 lbs. per square inch (all heat evolved would give 168 lbs.), the 
efficiency is T 6 ^ = 0*40 nearly. 

Calculated in this way the efficiency values for Oldham gas 
mixtures are : 

Prop, of Oldham gas in mixture . ^, fc, ^, ^, -j^, $, \. 
Heating efficiency . . 0*40, 0*48, 0*50, 0*43, 0*46, 0*40, 0*37. 

The furnace efficiency plainly diminishes with increased 
richness of the mixture in gas. 

Time of Explosion in Closed Vessels. 

The rates of the propagation of flame in explosive mixtures 
given in tables, pages 86 and 87, are true only where the 
inflamed portion is free to expand without projecting itself into 
the unignited portion. They are the rates proper for constant 
pressure. 

Where the volume is constant, in a closed vessel, the part first 
inflamed instantly expands and so projects the flame surface into 
the mass, compressing what remains into smaller space. 

To the rate of inflammation at constant pressure are added 
the projection of the flame into the mass by its expansion 
and also the increased rate of propagation in the unignited 
portion by the heating due to its compression by portion first 
inflamed. 

1 



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1 14 The Gas Engine 

It follows that the rate continually increases, as the inflamma- 
tion proceeds until it fills the vessel. 

This is evident from all the explosion curves. The pressure 
rises slowly at first, then with ever increasing rate till the explosion 
is complete ; thus the explosion curve for hydrogen mixture with 

air (- H ), shows an increase of 17 pounds in the first 0*005 

second, the maximum pressure of 80 pounds being attained in the 
next 0*005 second. With the weaker mixtures the same thing 
occurs, rise of pressure, slow at first, then more rapid, and in 
some cases becoming slow again before maximum pressure. The 
time taken to get maximum pressure varies much with the circum- 
stances attending the beginning of the ignition. If a considerable 
mass be ignited at once, by a long and powerful spark, or by a 
large flame, the ignition of the weakest mixture may be made 
almost indefinitely rapid. Something very like Berthelot's explo- 
sive wave may result. This is due to the great mechanical 
disturbance caused by the rapid expansion of the portion first 
ignited ; the smaller that portion is the more gently does the 
flame spread. A small separate chamber connected with the 
main vessel, if filled with explosive mixture and ignited, will 
project a rush of flame into the main vessel and cause almost 
instantaneous ignition. The shape of the vessel, too, has a great 
effect upon the rate. Where it is cylindrical and large in diameter 
proportional to its axial length, ignition is extremely rapid, the 
flame is confined at starting, and is rapidly deflected by the 
cylinder ends, and so shoots through the whole mass. 

By so arranging the explosion space of a gas engine that some 
mechanical disturbance is permitted, it is easy to get any required 
rate of ignition even with the weakest mixtures. 

The maximum pressure is not increased by rapid ignition. 

Starting the ignition from a small spark, the time taken to 
ignite increases with the volume of the vessel. 

Berthelot has experimented upon this point with explosion 
vessels of three capacities, 300 cubic centimetres, 1500 cubic 
centimetres, and 4000 cubic centimetres. He finds time of 
explosion (he also takes maximum pressure to indicate complete 



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Explosion in a Closed Vessel 1 1 5 

explosion) of mixture 2 vols. H, 1 vol. O, and 2 vols. N, in 300 
cubic centimetre vessel, 0-0026 second ; and in 4000 cubic 
centimetre vessel, 0*0068 second. 

With mixture of carbonic oxide and oxygen, 2 vols. CO, 1 vol. 
O, smaller vessel, 0*0128 second; larger vessel, 0*0155 second. 
Mixtures with air were much slower. The conclusion then is 
obvious, that in large engines the time of explosion will be longer 
than in small ones. 



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1 1 6 TJte Gas Engine 



CHAPTER VII. 

THE GAS ENGINES OF THE DIFFERENT TYPES IN PRACTICE. 

Having now studied the theoretic efficiency of the different 
kinds of engine and the mechanism of the heating method— that 
is the properties of gaseous explosions — the way is clear for 
the study of the results obtained from the engines in practice. 

It is quite evident that no practicable engine can give an 
efficiency at all approaching theory from the use of gaseous 
explosions ; the temperatures and therefore pressures produced 
fall far short of that due to the complete evolution of the heat 
present in the mixture as combustible gas. All the heat of 
the gas does not go to increase the temperature of the working 
fluid ; a large proportion of it is rendered latent in some way 
when the maximum temperature is attained. 

The appearance of the diagrams from the explosion of mixtures 
commonly used in gas engines, shows at first a very rapid increase 
of pressure and temperature, which terminates abruptly and is 
immediately succeeded by a fall which is relatively a slow one. 

It was formerly supposed that the completion of the explosion 
was coincident with the completion of the combustion, and there- 
fore of the evolution of heat. This, however, was shown by 
Bunsen and those who have followed him, to be untrue ; although 
the temperature ceases to rise, and fall sets in, the gas present 
has in few explosions been more than half-burned at the moment 
of maximum temperature. The causes which suppress the heat of 
the explosion and prevent it from being evolved at once are com- 
plex and have occasioned different explanations which will be fully 
discussed in a subsequent chapter. Meantime, it is sufficient 
to recognise the fact and to understand its bearing upon the 
economy of gas engines. 



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Gas Engines of Different Types in Practice 1 17 

It is a phenomenon common to all gas engines which have 
ever been constructed, whether using compression previous to ig- 
nition or not. The heat so suppressed appears when cooling sets in, 
and consequently explosive mixtures cool more slowly in appear- 
ance than would a mass of air heated to similar temperatures and 
exposed to similarly cold enclosing walls. 

In many gas engines the indicator diagrams are apparently 
almost perfect, that is, the lines of falling temperatures are 
almost true adiabatics. So far as the diagram yields informa- 
tion, the gases in expanding are losing no heat whatever to the 
cylinder, but the temperature is falling apparently only by work done 
upon the piston. This supposition is known to be untrue, because 
the gases are at a temperature often as high as the hottest of 
blast furnaces, and the walls enclosing are at most at the boiling 
point of water. It is the suppressed heat which is being evolved 
during fall of temperature which sustains the temperature and 
makes the diagram appear as if no loss or but little was going on. 
An actual engine therefore may give a diagram which is the exact 
theoretical one, and yet the efficiency of the engine be much 
below theory. The author's experiments upon explosive mixtures 
were undertaken to get the data necessary for the interpretation of 
the diagram, and the rising and falling curves, showing times of 
rise and fall of pressure, give the efficfency of coal gas in the 
different mixtures, apart altogether from theoretic considerations. 
Whatever the opinions held regarding the cause or causes of the 
suppression of heat, the experiments with carefully proportioned 
explosive mixtures, at known temperatures and pressures, deter- 
mine absolutely the capability of gas for producing pressure and 
for sustaining it under cooling. 

As the efficiency may be very different from that shown by 
the indicator, it is advisable to distinguish between the real and 
apparent efficiency. Call the one apparent indicated efficiency, 
and the other actual indicated efficiency. 

The apparent indicated efficiency, when multiplied by the effi- 
ciency of the gas in the particular mixture used, will give the actual 
indicated efficiency. For instance, if the diagram gave the efficiency 
of an engine as 0*29 and the efficiency of the mixture was 048, then 
the actual indicated efficiency is 0*29 x o*48=o'ii. That is, only 



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1 18 The Gas Engine 

0*48 of the gas present when the diagram is taken really acts 
in producing elevation of temperature; the remaining 0*52 is sup- 
pressed and keeps up the temperature, which would otherwise fall 
by cooling. The diagram alone can never tell accurately the 
losses which are taking place unless the heat is all evolved at once 
and appears in temperature; then, but not till then, will the lines 
traced by the indicator tell the loss of heat. Some previous 
writers have misinterpreted their indicator diagrams through 
neglect of this fact 

Some others, notably Dr. Slaby, of Berlin, have assumed that 
the phenomenon of retarded combustion is produced by invention 
and occurs only in the Otto engine. Thisis a mistake. Allengines 
using explosion necessarily exhibit it ; in fact, as it is an accom- 
paniment of all explosions, it is impossible to make an engine in 
which it is avoided. 

In the following examination of the performances of the 
various engines in practice the importance of the phenomenon will 
appear. 

Type 1. — The most important engines of this type which have 
yet been in public use are those of Lenoir, Hugon, and Bisschoff. 
Many others have been made and sold in some numbers, but as 
these three present fully all the peculiarities of the type, it would 
only waste time to describe the varied mechanical details consti- 
tuting the sole novel points in the others. 

Lenoir Engine. 

The Lenoir engine as made differs considerably from that 
described in his specifications. As a rule of almost general appli- 
cation, specifications are untrustworthy as accurate descriptions of 
working machines ; the author has been careful to describe no 
engine which he has not examined. 

Fig. 22 is a section of the cylinder of a half-horse power 
Lenoir engine. The engine in the Patent Office Museum, South 
Kensington, is well made and in external appearance closely re- 
sembles an ordinary high -pressure steam engine. 

The cylinder is 5^ inches diameter, and the stroke is Z\ inches. 
Its cylinder is provided with two valves ; both are slides, working 



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Gas Engines of Different Types in Practice 1 19 

between the cylinder faces and covers, which are held down to the 
slides by adjusting screws. One valve controls the discharge 
of the products of combustion, the other, the admission and 
mixing of the inflammable gas and air. The ignition is effected 
by the electric spark. The working cycle of the engine is as 
follows : 

When the piston is at the end of its stroke, the gas and air ad- 
mission valve is open ; the main port in it opens to the atmosphere, 



r Z**ffuj?VW*£ 




Plate \[ Wffi^ J -<GAS 

Fig. 22.— Lenoir Engine Cylinder (sectional plan). 

while a smaller port leads from the main port to the gas supply. 
The forward movement of the piston draws into the cylinder the 
air and the gas, which mix as they enter the main valve port and the 
engine admission port. At about half-stroke the supply of mixed 
gases is cut off, so that the cylinder is completely closed off from 
the atmosphere and from the gas supply ; an electric spark now 
passed into the explosive mixture from a battery and induction coils 
causes explosion and the pressure rapidly rises. The piston is 



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120 T/te Gas Engine 

chereby pushed on its stroke during the portion remaining to 
be completed ; at the end of the stroke the pressure has fallen 
by expansion doing work and by the cooling action of the cylinder 
walls, to nearly atmosphere again ; the exhaust valve opens and 
during the return stroke the products of combustion are expelled 
preparatory to taking in a fresh charge upon the next working stroke. 
The same operation is repeated upon the other side of the piston 
so that the engine is double-acting of a kind. It cannot be con- 
sidered as truly double-acting, like the steam engine, as the driving 
pressure is not acting during the whole forward stroke, but only 
during that portion of it which is not taken up in sucking in 
the explosive charge. The fly wheel, because of this, is much 
larger than in a steam engine of corresponding dimensions, 
and the power is also much less. The valves are both actuated by 
eccentrics upon the crank shaft. Each slide requires a separate 
eccentric because the exhaust during the whole stroke and the 
admission during only half-stroke could not be managed by the 
single to and fro movement To get the best result it is evident 
that the least possible power should be expended in introducing 
the charge ; therefore, large inlet air ports are required, all the 
larger because an eccentric cannot be made, alone, to give a 
sudden cut-off. To prevent throttling as the ports approach 
the closing points, the total opening must be considerable. The 
eccentric is so set that the port is open slightly before the crank 
has crossed the centre, so that it may be well open when the 
charge begins to enter. In fact it has some lead like a steam 
slide, and for the same purpose. The exhaust valve is set 
precisely as in the steam engine, and is of similar construction, 
except that it is not enclosed in a case, but it is held against the 
cylinder face by a cover and screws. Fig. 22 is a sectional plan 
of the cylinder, showing the valves and ports ; fig. 23 is a trans- 
verse vertical section of the cylinder, showing the valves and valve 
covers with gas, air and exhaust ports. The arrows indicate the 
direction of the gas and air flow, while mixing and entering the 
cylinder, also the exhaust path. As the air port opens to the 
cylinder slightly before the piston has completed its stroke, and 
a slight pressure may yet remain in the cylinder, the gas port 
does not open till a little later. The gas and air do not open 



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Gas Engines of Different Types in Practice 121 

quite simultaneously, although nearly so ; neither do they close 
quite together. There is one gas admission port in the slide 
leading into the main port ; in the cover there are two ports 
between which the slide port passes, taking gas from either, as 
is required, for the end of the cylinder which is receiving the 
charge. The main valve port opens on the upper side to the air, 
and is covered by a perforated plate and a light metal case 
furnished with a throttle valve ; the brass plate perforated is 
carried downwards and covers the gas port, so that the gas 
entering from the supply pipe is not permitted to flow at once into 



t\h.'i r 



Air 

Gas and 

Air mix at 
this point 




Gas Inlet 

Fig. 23.— Lenoir Engine Cylinder (transverse section). 

the main port, but must first pass up through the perforations and 
mix with the air which is going down through those adjoining. 
The mixing arrangement is somewhat imperfect, and is exceed- 
ingly sensitive to change of speed in the engine. The throttle- valve 
is intended to increase or diminish the supply of air ; by closing 
it slightly, the suction upon the gas port is increased, and so 
the proportion of the mixture altered. By opening it, the air has 
freer access to the cylinder, the pressure is not reduced so much, 
and therefore the gas is diminished The mixing, however, is too 
irregular ; as the gas streams are not projected separately into the 



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122 Tlu Gas Engine 

incoming air stream, the gas flows too much in mass into the air 
in mass. The igniting points were invariably placed at the upper 
part of the cylinder in the cylinder covers. The cylinder and covers 
are waterjacketed, the water is kept continuously flowing through, 
so that the temperature may not become so high as to injure the 
cylinder. This is a most necessary precaution in any gas engine 
of even moderate power ; the effect of neglect in a Lenoir engine 
is very soon observed in complete cutting up of the cylinder ; it 
speedily becomes red-hot if allowed to run without water. In- 
deed, even with an adequate water supply, the larger engines gave 
great trouble ; although the cylinder could be kept cool the piston 
could not. It was proportioned too much on steam engine lines, 
and when working at full power the incessant explosions upon both 
sides caused so rapid a flow of heat into it that the small surface 
exposed to the water jacket by the circumference was insufficient 
to carry away the heat absorbed by the whole piston area. The 
pistons often became red-hot. 

The exhaust slide also had rather hard work, and required 
delicate adjustment, as the exhaust gases were very hot, often 
8oo° C. ; the expansion of the slide was therefore considerable, 
and in order to be pressure tight when hot, the adjusting screws 
had to be kept rather easy when cold. The engine when 
starting, therefore, always leaked a little at the exhaust valve. 
The same thing happened with the admission slide, but to a lesser 
degree. 

Notwithstanding the large area of the admission port and the 
lead given to the admission valve, the closing motion was too 
slow to prevent throttling ; accordingly the pressure fell some- 
what below atmosphere, while the valve was cutting off preparatory 
to explosion. After cutting off a slight delay occurred between the 
passing of the spark and the commencement of the explosion ; 
the explosion itself took some time to complete ; it was by no 
means instantaneous ; the diagram produced was consequently 
imperfect. In addition to all this, the piston being so hot, heated 
the charge while it was entering, and so occasioned further 
loss. 

The lubricating arrangements also were primitive. The 
steam engine requiring but little care in lubricating, the gas 



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Gas Engines of Different Types in Practice 123 

engine was not supposed to require more ; and the ordinary lubri- 
cating cock was deemed sufficient. All these sources of loss, 
inevitable in a first attempt, made the engine comparatively in- 
efficient. Notwithstanding all its defects, the Lenoir engine at the 
time of its production was the best the world had yet seen, and in 
careful hands it did good work and created a widespread interest. 
The engine in South Kensington Museum, under the skilful care of 
Mr. S. Ford, worked for many years supplying all the power required 
for the repair department of the Patent Office Museum. It runs with 
perfect smoothness, nothing whatever in its action would enable 
one standing beside it to imagine for a moment that the motive 
power was explosive. The popular notion of an explosion is always 
associated with the idea of a great noise. This, of course, physicists 
have always known to be a fallacy, as no explosion makes noise 
unless it has access to the atmosphere. An explosion in a closed 
vessel makes no sound unless the vessel bursts. In a gas engine 
it is only necessary to see that the explosion is not too rapid, but 
that time is allowed for the slack of the connecting rod and crank 
connections to take up. The explosions used by Lenoir were 
seldom more rapid in rise of pressure than is common with all 
steam engines. A 1 -horse Lenoir engine inspected lately by the 
author at Petworth House, Petworth, had been at work for the 
past twenty years pumping water for the town and is still at work 
It works with smoothness and is altogether more silent in its action 
than most modern gas engines. The author finds that many Lenoir 
engines are still at work after twenty years' continuous use, notably 
two 1 -horse power engines at the Brewery of Messrs. Trueman, 
Hanbury and Buxton, London, and one 1 -horse power at the 
establishment of Messrs. Day, Son and Hewitt, Dorset Street, 
London, all doing hard work with great regularity. 

Diagrams and Gas consumption. — Prof. Tresca of Paris has made 
experiments with a £-horse Lenoir engine, and found that it con- 
sumed 95 cb. ft. of Paris gas per indicated horse power per hour. The 
diagrams from so small an engine hardly do justice to the method, 
and as it is desirable to compare the engine with modern engines 
using similar volumes of charge the author has taken a diagram from 
a paper by Mr. Slade, published in the Journal of the Franklin 
Institute, Philadelphia. The engine had a cylinder of eight inches 



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124 



The Gas Engine 



diameter and sixteen stroke. The explosion space corresponds 
closely to that of the author's experimental explosion vessel. 

The diagram, fig. 24, at once shows the truth of the preceding 
discussion of the action of the engine. 

AB is the atmospheric line, traced upon the indicator card 
by the pencil before opening the indicator cock to communicate 
with the interior of the cylinder ; it is the neutral position of the 
indicator piston while the pressure on both sides of it is at atmo- 
sphere ; any pressure from within the cylinder pushes up the piston 
and therefore the indicator pencil. Pressure above atmosphere 
is registered by lines above that line, pressure below atmosphere 






B 



Diagram at 50 revolutions, cylinder 8J inches diameter, 16J inches stroke. 
Fig. 24.— Lenoir Engine Diagram. 

is registered by lines below that line. The card shows three dis- 
tinct tracings, each corresponding to one stroke of the engine : 
admission of the charge, explosion, expansion and return expel- 
ling the products of the combustion. If the cycle is carried 
out in a mechanically perfect manner the admission of the charge 
should be accomplished without loss by throttling. This is not so. 
From the point a to the point b the valve is open enough to give 
free access to the cylinder, and accordingly the pressure within the 
cylinder is not appreciably lower than that without ; but here the 
valve begins to contract its opening at the very moment that 
the piston is moving most rapidly, the pressure falls and is a couple 
of pounds per square inch below atmosphere when it closes. 
When closed, the spark does not at once take effect, so that the 
pressure has become n lbs. per sq. in. total, before the igni- 



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Gas Engines of Different Types in Practice 125 

tion begins to cause a rise. Then the ignition itself takes some 
time to be completed, here about J 7 second ; the piston has, 
therefore, moved through a further one-and-a-half-tenth of its 
stroke and the heat given by the explosion is not added at strictly 
constant volume, as required by theory. Apart altogether from 
loss of heat to the cylinder walls, this diagram is mechanically im- 
perfect. The valve arrangements should be such that no loss is 
incurred in charging and that the explosion follows so rapidly that 
the pressure in the cylinder has no time to fall by expansion, 
after closing the admission ; the explosion, indeed, should at once 
follow the cut-off. In the best of the three lines the pressure has 

3035 C. absolute 



1534° C. abs. 






•1246° C. abs. 



' 1 ocre 



Fig. 25. — Lenoir Engine Diagram. 

fallen to nearly 1 1 lbs. total, and the maximum pressure of the 
explosion is 48 lbs. per square inch total. The average of the 
three lines gives a pressure divided over the whole stroke of only 
8*3 lbs. per square inch, which, assuming the diagram from the 
other end of the cylinder to give similar results, gives a total of 
2 indicated horse power at 50 revolutions per minute. This is 
an exceedingly poor result for so large an engine. The apparent 
indicated efficiency is much below that of a theoretical diagram 
using the same expansion. Fig. 25 shows in dotted lines a 
diagram which will have the same efficiency as the actual diagram 
(best of the three lines). If the temperature of the entering 
charge has been raised to ioo° C, as stated by Mr. Slade, then 
the point c upon the diagram corresponds to that tempera- 
ture; the point d will correspond to a temperature of 2035 C. 
absolute, as the volume has increased from 0*4 to 0*5 and the 



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126 The Gas Engine 

pressure from n lbs. to 14-7 lbs. per square inch total at the point 
e. The area of the part of the explosion curve def may be taken 
as equal to the part of the diagram cfg which is resistance due to 
the valve action ; the work done upon the piston by the one part 
balances the loss by the other 3 both portions may therefore be 
neglected, the dotted lines representing the apparent diagram 
efficiency. 

The temperatures for calculating maximum possible efficiency 
are as follows— they are also marked upon the diagram 

t 2 °35° absolute. 

t 1 1534° 
t 623 

/ l 1246 

Calculating e from formula (17) p. 57 

L _, _ (T'-/»)+ I-4Q8 (/'-/ ) 
T — / 

_ j _ (1534- I246) + r40 8 (12 46 - 623 ) 
2035-623 

= 0*175. 

The apparent indicated efficiency for the best of the three 
lines is 0-175. If it were constantly repeated, the actual indicated 
efficiency may be obtained by multiplying by the efficiency of the 
gas in the mixture used to get the explosion. The numbers got 
from explosion in a closed vessel do not quite represent the con- 
ditions of loss in a cylinder with a moving piston. In the first 
case the loss ot pressure and temperature is due solely to the 
cooling effect of the vessel's walls; in the second the moving 
piston reduces pressure and temperature by expansion, and at the 
same time increases the surface exposed. The increased surface, 
however will not increase the rate of cooling, as the volume is at 
the same time increased in a greater proportion. It has been 
already shown that cooling of a heated mass of gas is indepen- 
dent of the pressure, and depends on the ratio of surface to 
volume. 

In the engine the volume of the hot gases becomes doubled by 



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Gas Engines of Different Types in Practice 12; 

expansion, but the surface exposed does not double; the cylinder 
surface increases with the volume, but the piston area and cylinder- 
cover area remain the same, so that the proportion of surface to 
volume diminishes instead of increasing. The heat lost to the 
cylinder and piston and cover in the engine will therefore be no 
greater than that lost to the enclosing wall of the experimental 
explosion vessel in a similar time. It will indeed be somewhat 
less, as in the time taken doing work the temperature will fall by 
heat disappearing as work. With the closed vessel the fall is due 
solely to cooling, so that the average temperature during the time of 
exposure is higher. More work is urgently required by careful 
physicists to get accurate data. At present the approximation to 
the efficiency of the gas in different mixtures by closed vessel 
experiments is the best that can be had; it cannot be greatly in 
error. The efficiencies obtained from the indicator diagram and 
the author's experiments will be lower than the truth, the more so 
the greater the expansion. With engines as at present constructed 
the difference is but small. 

The mixture required to give a temperature of 2035 ° C. absolute 
is, for Oldham gas, 1 gas 6 air, and the average pressure during 
0*3 sec. from complete explosion is 63 lbs. per square inch above 
atmosphere, nearly. The time taken to expand in the engine 
after explosion is 0*3 sec. ; the pressure which should be produced 
by the explosion of this mixture, if all the heat of the gas went 
to heat the air and products, 192 lbs. per square inch above atmo- 
sphere. That is, the difference between 192 and 63 has gone in 
heat suppressed at the moment of complete explosion and heat 
lost while exposed to the influence of the vessel walls during the 
same period as the effective stroke of the engine. 

The efficiency of the gas in the mixture is therefore 

- 3 2 = °'33 nearly, 

that is, only one- third is really effective in raising temperature. 
The actual indicated efficiency will, therefore, be only one-third 
of the apparent. Three times the amount of heat accounted for 
by the diagram is required to make the gases used in the explosion 
show the temperatures and curve of the diagram. 



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1 28 The Gas Engine 

Apparent indicated efficiency x efficiency of gas = actual 
indicated efficiency : 

0175 x 0-33 = 0-058 

The actual indicated efficiency of the engine is 0*058 or 5*8 
per cent, if this diagram be constantly repeated; but as it is the 
best of the three lines it requires correction. Taking the worst of the 
three diagrams, fig. 24 shows the temperature as follows : t, 2035 
absolute; t 1 , 1697 absolute ; /, 797 ; /', 1243 absolute. 

The apparent indicated efficiency is e = 0*126. 

The actual indicated efficiency is 0*126 x 0*33 = 0*0495 or 
4 '95 P er cent - °f t^ e tota ^ neat given to the engine. 

Tresca calculates the heat transformed into work by the Lenoir 
tested by him as 4 per cent. 

The mean of the best and worst of these diagrams is 

4l±i35-S-37. 

2 

which is higher than the result obtained by this distinguished physi- 
cist ; but the difference is sufficiently accounted for by the differ- 
ence in the dimensions of the engines. Tresca's was only half- 
horse, Slade's was two horse. 

The Lenoir engine used mixtures ranging in composition from 
1 gas and 6 vols, air to 1 vol. gas and 1 2 vols, air, depending upon 
the amount of work upon the engine ; when there was little work 
the governor was arranged to throttle the gas and so diminish the 
proportion present This was a bad plan, as will be explained in the 
chapter upon governing. But the effect was to make the engine 
use all grades of ignitable mixtures from the strongest to the 
weakest. Apart, however, from all intentional arrangements for 
governing, these engines tended to govern themselves. An increase 
of speed always causes the proportion of gas in the mixture to 
diminish, because the resistance of the small gas port to flow 
increases more rapidly than the larger air port It follows that if 
the ports are proportioned to pass certain volumes at a low rate of 
speed, at a higher rate the proportion is disturbed, the smaller 
port giving a greater proportional resistance. The effect is seen 
in all the diagrams, the ignitions become later and later as the 
mixture diminishes in inflammability, and after attaining a certain 



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Gas Engines of Different Types in Practice 1 29 

dilution, ignition ceases altogether, or becomes too slow to be of 
any practical use. In the Lenoir type of engine too slow ignition 
is an unmixed evil, as the theory of the engine requires rapid igni- 
tion. In it the loss of efficiency due to valve and igniting arrange- 
ments is considerable. The electric ignition is very delicate and 
troublesome. To overcome the defects of the Lenoir, Hugon 
introduced his engine, which in some respects was a considerable 
advance. 

Hugon Engine. 

The Hugon engine, like the Lenoir, exploded the charge drawn 
into the cylinder by the piston at atmospheric pressure : in it, 
however, greater expansion and more dilute mixtures were used. 





Fig. 26. 



Hugon Engine Cylinder. 



Fig. 27. 



Fig. 26 is a sectional plan showing valves, passages and the 
cylinder and piston. Fig. 27 is a transverse vertical section 
through the cylinder at the line a b. The admission of the charge 
and the expelling of the exhaust are accomplished through the 
same passage, so that the cylinder has only two ports, as in the 
steam engine ; two valves are used, one working outside the other. 
The inner valve has five ports, two for admitting the charge, one 
for exhausting, and two for carrying the igniting flame. The 
ignition by flame was first accomplished in a workable manner by 
Hugon, although it had been described in several patents long 
before his time. 

The ports marked 1 1 in the inner slide a are admission, the 



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1 30 The Gas Engine 

ports marked 2 2 in the inner slide are igniting, ports ; the port 3 
is the exhaust passage, alternately communicating with each end 
of the cylinder by the long ports 4 4 to the exhaust port 5, pre- 
cisely as in a steam engine. The action of the admission ports 
is somewhat novel. The object is to secure a rapid opening and 
cut-off, bringing the igniting flame on immediately after closing 
the cylinder. The valve is actuated from a cam. When the 
piston is at the end of its stroke and is moving forward, the 
valve a is moving in the same direction, the port 3 is allowing 
the exhaust gases to escape from the other side of the piston, the 
port 1 is open to the cylinder and is communicating through the 
port 6 or 6, in the outer slide e, with the air and also with 
the gas supply. When the piston has taken in sufficient charge, 
the cam moves the slide a suddenly forward, so causing the port 1 
to close on the outer side but not on the inner ; the igniting 
port comes on and the flame burning in it inflames the mixture, 
filling the engine port, from whence it spreads into the cylinder 
itself. As the inner valve cuts off when moving in the same 
direction as it does when opening, it is evident that it must cross 
back again, to be in the position required to commence opening 
at the correct time. While crossing, unless the communication 
with the atmosphere and gas supply is stopped in some other way, 
it will open at the wrong time ; to prevent this, the outer valve b 
is provided. It is actuated from a pin projecting from the main 
valve a ; this pin 7 works in the slot 8, and while the main valve 
is moving forward after cutting off, the pin strikes the end of the 
slot and carries the outer valve with it, causing it to close the port 
in the cover which it commands. A small plate and spring give 
friction enough to keep the valve in position till it is moved in 
the other direction. When the main valve returns, although its 
ports open on the engine ports, the outer ends are blinded by the 
outside valve which is not again opened till the main valve has 
closed. By this ingenious contrivance, a rapid admission and 
cut-off are secured with one cam and the main and auxiliary 
slides. The engine from which these details are taken is in South 
Kensington Museum and is rated at i-horse power. The valves 
are arranged to cut off at about one-third stroke. 

The cylinder is 8^ diameter and 10 in. stroke. The clearance 



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Gas Engines of Different Types in Practice 131 

spaces due to the long ports 4 4, the valve ports open to the 
cylinder at the moment of explosion, and the space into which the 
piston does not enter, make up in all a proportion of products of 
combustion equivalent to nearly thirty per cent, of the entire charge. 
The effect of this is to cause a considerable difference between 
the nature of the mixture in the port and that in the cylinder 
itself, the port mixture being much more inflammable than that 
in the cylinder. As a consequence the ignition is more rapid 
with weak mixtures than in the Lenoir. The gas is supplied to 
the air port in regulated amount by means of a bellows pump 
worked from an eccentric on the crank shaft ; it mixes with the air 
in passing through the valves and port ; the products of combustion 
are therefore completely expelled from the port, and nothing but 
pure mixture left to be inflamed by the igniting arrangement. 
The gas for the internal igniting flame is supplied also from a 
bellows pump under slight pressure. This flame is extinguished 
by each explosion, and is relighted when the port opens again to 
the air by a constant external flame. The action of the exhaust 
port in the main slide is so evident as to require no other 
explanation than that afforded by the drawing. 

The engine works very smoothly, and is a great improvement 
upon Lenoir in certainty of action ; all the trouble with the 
battery and coil is very simply avoided. To prevent overheat- 
ing of the piston, water is injected by means of a tap ; it is 
adjusted so that each suck of the engine drawing in mixture also 
takes in enough water to keep the piston at a reasonable tempe- 
rature. In this the engine was successful ; it was capable of 
harder and more continuous work than the Lenoir, and was in 
every way more certain in its action even with a considerable 
variation in the composition of the explosive mixture used. The 
only parts which gave trouble were the bellows pumps controlling 
the gas supply to cylinder and igniting port ; these were made of 
rubber, and deteriorating after some use gave trouble by leaking 
and occasional bursting. In some of the engines in use they 
were replaced by metal pumps and a mixing valve. With these 
additions the engine in the Patent Office Museum ran for many 
years. 

Diagrams and Gas Consumption. — According to, Professor 



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132 



The Gas Engine 



Tresca, the gas consumed by a Hugon engine of 2 -horse power 

was 85 cubic feet per indicated horse per hour. 

Fig. 28 is a diagram taken from 
a ^-horse engine by the author. 
The engine was indicating 078 
horse power, the average pressure 
being 3-9 lbs., and the maximum 
25 lbs. per sq. in. The card shows 
considerable delay in explosion after 
cut-off, notwithstanding the rapid 
movement of the igniting slide. 

Bischoff Engine. 

The consumption of the non- 
compression type of engine is too 
high to permit of its use in any but 
the very smallest machines ; accord- 
ingly the Lenoir and Hugon engines 
have long disappeared from the 
market, and the type survives 
mainly in the Bischoff, which is 
specially designed for small powers, 
mostly under half-horse. It is an 
exceedingly ingenious little engine, 
and presents many interesting pe- 
culiarities. 

Fig. 29 is a side elevation, part 
in section ; fig. 30 a section arranged 
to explain the valve action. In both 
figures the similar parts are marked 
with similar letters. There is no at- 
tempt to gain economy by attention 
to theory ; the aim is to get a small 
workable engine with the least possible complication. In this it is 
very successful. To avoid the complication of a water-jacket, 
the cylinder and piston are so arranged that heating is allowable. 
The engine is upright and very peculiar in appearance, the 
cylinder has cast on it a number of radiating ribs, which by 




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Gas Engines of Different Types in Practice 133 

contact with the air cause conduction of the heat more rapidly 
than would otherwise occur. The temperature, however, becomes 
very high, and provision is made to prevent injury to the piston. 
It is fitted loosely to the cylinder and has no rings, the connecting 




Fig. 29. 



Fig. 30. 



Bischoff Engine. 



rod arrangement is seen in the figure (29) ; it takes the thrust of the 
explosion in tension, and almost without side pressure upon the 
guide. Any side pressure upon the guide is quite prevented from 
reaching the piston, and it consequently is never rubbed against 



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134 Tlu Gas Engine 

the cylinder. The pressure of the explosion is so slight that the 
leakage is not serious even without rings. The piston moves up, 
taking in the charge, the air through the valve i, fig. 30, which is 
simply a piece of sheet rubber backed by a thin iron disc. The 
pressure of the air opens, and the explosion closes it ; the valve 2, 
fig. 29, similarly made but smaller, admits the gas ; the mixture 
does not form till the gases have passed the point 3, fig. 30; 
therefore the explosion does not spread back to the valves. 
When the piston gets to the point 4, it crosses a small aperture 5 
covered by a light hanging valve ; a flame burning outside in the 
flame chamber is drawn in. The explosion then occurs, and the 
pressure at once closes all valves and propels the piston. On the 
return stroke, the piston valve 7 opens to the exhaust pipe 8, at the 
same time closing the passage to the air admission valves. The 
cylinder proper requires no lubrication; the guide requires a 




Scale 1 in. = 24 lbs. : 3 J" diam. of cylinder ; xxi ins. stroke. 

Fig. 31. 
Diagram from i-man power Bischoff Engine ; 112 revs, per min. \CUrk.) 

little, but the projection of the cover and a draining hole prevent 
accumulation and overflow of oil into the cylinder. This pre- 
caution is very necessary, because of the high temperature of both 
piston and cylinder; without it speedy charring and choking 
up of the cylinder would result. The arrangements are crude 
and the engine is somewhat noisy, but it is very reliable, and suits 
the purpose for which it is designed exceedingly well. 

Diagrams and Gas Consumption. — The diagram is very similar 
to the Lenoir. Fig. 31 is a diagram taken from a i-man power 
engine by the author. 

The consumption is, as might be expected, rather higher than 
Lenoir. According to tests made at the Stockport Exhibition it 
uses 1 20 cubic feet per actual horse power per hour. 



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Gas Engines of Different Types in Practice 135 

Type (Ia). 

Free Piston Engines. — The very high consumption of gas 
common to the engines described prevented their extended use, 
and set inventors to work to produce some method which would 
give better results. It was very obvious that there was a large 
loss of heat ; the trouble with cylinders and pistons made this 
abundantly evident. Devices proposed for increasing power by 
the injection of water spray, and steam, in various ways failed 
to produce good effect except in aiding lubrication. The inventors 
of the day seem to have reasoned somewhat in this fashion. The 
force generated by an explosion of gas and air is an exceedingly 
evanescent one, a high pressure is produced, but it lasts only for 
a very short time ; if work is to be obtained before loss by 
cooling absorbs all the heat, it must be done rapidly. The 
reason why the Lenoir and Hugon engines give so poor a result 
is a too slow movement of piston after the explosion. Therefore, 
if a method can be devised permitting greater piston velocity, 
better economy will be obtained. In this reasoning there was 
considerable truth. It has been already proved that the shorter 
the time of contact between the charge after explosion and the 
enclosing walls, the greater will be the efficiency of the gas in the 
mixture. But this only holds within certain limits. If the expan- 
sion is too rapid before explosion is complete, then a loss instead 
of a gain will occur ; the expansion should not commence till 
maximum pressure is attained or it will cause a loss of pressure. 
Indeed, it is quite conceivable that in engines of the Lenoir type, 
the expansion might be so rapid, relatively to the rate of explosion, 
that no increase of pressure at all resulted ; in which case no power 
whatever would be obtained. The gain then to be expected 
arises from rapid expansion after complete explosion. This has 
been carried out by several inventors by the free piston method. 
Instead of expending the force of the explosion upon a piston 
rigidly connected to a crank, the piston is allowed free movement. 
The explosion launches it against the atmosphere ; it acquires 
considerable velocity, which is expended in compressing the 
exterior atmosphere, that is, in producing a vacuum in the cylinder. 
When all the energy of motion is expended, the piston comes to 



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1 36 The Gas Engifie 

rest, and the atmospheric pressure forces it back again. So soon 
as the return movement commences, a clutch contrivance engages 
the shaft and drives it. Engines of type 1 A may be described as — 

Engines using a gaseous explosive mixture at atmospheric 
pressure before explosion ; the explosion acting on a piston free to 
move without connection with the crank shaft, the velocity being 
absorbed by the formation of a vacuum. The power is given to 
the shaft on the return stroke under the pressure of the atmo- 
sphere. 

As has been stated in the historical sketch, the first to propose 
this kind of engine were Barsanti and Matteucci, 1857, but the 
difficulties were not sufficiently overcome until the invention of 
Otto and Langen, 1866. 

Otto and Langen Engine. — This engine consists of a tall vertical 
cylinder surrounded by a water jacket ; in it works a piston which 
carries a rack instead of a piston rod; the mouth of the cylinder is 
open to the atmosphere. Across the top of the cylinder is carried 
the fly-wheel shaft ; it cannot be called the crank shaft because 
there is no crank. On the shaft there is a toothed wheel which 
engages the teeth of the rack ; it runs freely on the shaft while the 
piston is on its upward stroke, but by an ingenious clutch arrange- 
ment it grips the shaft when the piston moves down. The shaft is 
therefore free to rotate in one direction and the piston is free to 
move up without restraint, but in moving down it gives the impulse. 
The shaft is carried on bearings bolted to the top of the cylinder, 
which forms a strong and convenient column for carrying the 
mechanism required to accomplish the cycle of the engine. At 
the lower end of the column is placed a slide valve which performs 
the treble duty of admitting, igniting, and discharging. It is driven 
from an intermediate shaft, intermittently, as determined by the 
governor of the engine. When working at full load, the move- 
ment of a small crank actuated from the shaft, lifts the rack and 
piston through some inches, taking in the charge through the slide 
valve, which then moves further and brings in the igniting flame. 
The explosion ensues and shoots up the piston with consider- 
able velocity, the pressure rapidly falls by expansion and soon 
gets to atmosphere. The piston however has been moving freely 
and therefore has done no work ; all the energy of the explosion, 



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Gas Engines of Different Types in Practice 137 

however, has been given to it. The piston has the energy of explosion 
in the form of velocity ; it moves on, the pressure beneath it falling 
below atmosphere until all its energy of motion is absorbed in 
forming the vacuum. When this occurs it ceases its upward flight 
and returns, the outer atmosphere driving it back, and as the clutch 
has engaged the shaft, an impulse is givea The actual work is 




Fig. 32. — Otto and Langen Engine (vertical section). 

therefore done by the atmosphere on the down stroke, the explosion 
being spent in obtaining energy in a form conveniently applic- 
able. If no cooling of the hot gases occurred upon the down 
stroke the compression line would return to the point where the 
expansion line touched atmosphere ; then the exhaust valve would 
open and the gases would be discharged at atmospheric pressure- 



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1 38 The Gas Engine 

In that case the work done by the atmosphere and weight of piston 
on the downward stroke would exactly equal the energy of the ex- 
plosion while falling by expansion to atmospheric pressure. But the 
cylinder does cool the gases while on the upward and downward 
stroke, so that the expansion line does not return upon itself ; the 
amount of fall below the expansion line is gain and is added to the 
energy of the explosion just as the condenser adds to the efficiency 
of the expansion of steam. The exhaust gases are expelled by the 
piston and a new stroke is commenced. At full power the piston 
makes about 30 strokes per minute, the shaft rotating about 90 
revolutions per minute. The governor of the engine is so arranged 
that when the speed becomes too great, a lever disengages a pawl 
from a ratchet and disconnects the small crank lifting the piston. 
The charge is not taken in till the speed falls, and then the pawl 
is again allowed to connect the small crank to the main shaft. 
The ignition slide gets its motion from the small crank shaft, so that 
it is arrested or moved along with the piston. The piston 
remains at the bottom of the stroke till it is wanted for another 
explosion. 

Fig. 9, p. 21, shows the general arrangement of the engine, and 
fig 32 is a vertical section showing the clutch and section of the slide 
valve. Fig. 33 is an elevation, part in section. 

a is the cylinder; b is the piston to which is attached the 
rack c ; d the toothed wheel containing the clutch engaging 
the rack to the power shaft. The rack is strongly guided. e is 
the fly-wheel shaft on which is keyed the fly wheel f and the 
driving pulley g ; h water jacket ; 1 the port for inlet of the 
explosive mixture and discharge of the products of combustion ; 
k the slide valve serving to admit, to ignite the charge and to dis- 
charge the products of combustion ; it is actuated from the small 
shaft l by the pin m ; the ratchet n and the pawl o connect the 
small shaft to the main shaft when requisite, as determined by the 
governor lever p. 

This engine is the result of great care and labour on the part 
of the inventors; it is greatly superior in economy and efficiency 
to any preceding it, and its only fault is its excessive bulk and 
weight and the great noise made by it when in action. The whole 
of the energy of the explosion being expended in giving the piston 



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Gas Engines of Different Types in Practice 139 

velocity, just as in a cannon, the recoil is considerable. So 
serious is it that none but the very smallest engines can be placed 
upon upper floors without special strengthening. The author has 
seen an engine at work where the vibration produced was so great 
that props were put under the engine from floor to floor through 
four floors to get a solid resistance in the basement 




Fig. 33.— Otto and Langen Engine (elevation). 

In other cases strong iron beams placed diagonally at the angle 
of a stone wall carried the engine; notwithstanding these precau- 
tions much vibration was caused. These difficulties did not 
seriously affect the sale of the engine for small powers, but they 
quite prevented it being made for powers above 3-horse. The 
clutch also is a matter of great difficulty, the whole power of the 



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140 



The Gas Engine 



engine passes through it and it must act freely and instantaneously. 
The faintest back lash would allow the accumulation of so much 
velocity by the return that even a strong arrangement would be 
destroyed. For this reason the pawl and ratchet of Barsanti and 
Matteucci failed completely. 





e 






^ 




\ 










1 ^ 


i 




. : . ,. , 






X T X 


/ 






Q 






Messrs. Otto and Langen's clutch is one of the main points of 
their invention and is excellent. It is shown in detail at fig. 34. 
The part a is keyed to the shaft; on it runs the part b carrying 



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Gas Engines of Different Types in Practice 141 

the teeth engaging the rack. So long as b moves in the direction 
of the arrow 1, or is stationary, a revolves freely with the shaft in 
the direction 2. The steel slips ^,r,^^are wedge-shaped on the 
back, so is the interior of the part b at the positions d, d, d, d. 
So long as the rack is stationary or ascending, the steel rollers 
e,e t e,e, run freely clear of the inclined surfaces ; immediately the 
rack moves down at a rate greater than the movement at a, then 
the rollers are firmly wedged between the two inclined surfaces 
and the steel slips r, c> c, c grip the part a firmly and drive the 
shaft. When the bottom of the stroke is reached the wedges loose 
again and the piston is free. 

Diagrams and Gas Consumption. — The author has made a set 
of experiments upon an engine of 2-horse power working with 
Oldham coal gas. 

The cylinder is 12*5 inches diameter and the longest stroke 
observed was 40*5 inches. Working at the rate of 28 ignitions 
per minute, the indicated power was 2-9 horse, and the gas was 
consumed at the rate of 24*6 cubic feet per i.h.p. per hour. The 
brake power is 2 horse, so that the brake consumption is at the 
rate of 36 cubic feet per horse power per hour. This does not 
include the consumption of the side lights which is in all 12 cubic 
feet per hour. 

Fig- 35 is a diagram from the engine when at full power. 

The full line is that traced by the indicator, and the dotted 
line is the real line of pressures marred by the oscillation of the 
indicator pencil. 

Professor Tresca. tested a half-horse engine at the Paris Ex- 
hibition of 1867; it gave 0*456 brake horse, and consumed gas at 
the rate of 44 cubic feet per brake horse power per hour. This es- 
timate did not include the side lights. The author's test gives a 
better result than that of M. Tresca, but this is due to the fact of 
the larger engine being used. It is probable that a 3-horse engine 
would give a consumption of about 30 cubic feet per brake horse 
power per hour. 

The interest excited by the engine at the time of its first trial 
was naturally great, and many explanations were advanced of the 
cause of its superiority over the Lenoir and Hugon engines. 
Strangely enough the theory of the engine has been at best but 



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142 



TJte Gas Engine 



imperfectly stated by previous writers; some indeed have fallen 
into grave error respecting its action. It is therefore essential 
that it should be somewhat fully considered here. 




The name by which it is most widely known is in itself mis- 
leading. Atmospheric gas engine at once suggests the Newcomen 
steam engine and further suggests the substitution of flame for 



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Gas Engines of Different Types in Practice 143 

steam, vacuum in both cases being supposed to be produced by 
condensation. In the steam engine the name truly describes the 
action : the piston is drawn up, the cylinder filled with steam at 
atmospheric pressure and the steam condensed by a water jet ; 
then the atmosphere presses the piston down and gives the power. 

In the gas engine cooling has little to do with the production 
of the vacuum ; the vacuum would be produced and the engine 
would act efficiently without any cooling action of the cylinder 
whatever. The diagram fig. 35 proves this very clearly. While 
the piston is moving from the point a to b by the energy stored 
up in the fly wheel, the charge enters the cylinder; at b the piston 
pauses, and, the igniting flame being introduced, the charge ex- 
plodes, the pressure rises to 54 lbs. per square inch above atmo- 
sphere. The appearance of the explosion curve does not indicate 
truly the rate of increase, because the piston is completely at rest 
till the pressure puts it in motion. The piston moves up impelled 
by the pressure of the explosion; as it moves the gases beneath it 
expand and therefore the pressure falls. At the point d the pres- 
sure is again level with that of the outside atmosphere; here the 
explosion ceases to impel the piston and, the pressure in the cy- 
linder falling, the atmosphere presents a continually increasing 
resistance. But while the piston is passing from the point b to d> 
the pressure has been falling from 54 lbs. above atmosphere to 
atmosphere ; the average pressure upon it through this distance is 
12*6 lbs. per square inch; as the distance is 1*3 feet and the piston 
area is 1227 inches, 2010 ft. pounds have been expended upon it. 
What becomes of this work ? In an ordinary engine it would be 
communicated to the crank, and if no load were on, the crank 
would give it to the fly wheel. Here there is no crank and the 
piston is perfectly free, the piston alone contains the energy ; its 
weight has been raised through 1 -3 feet and the balance of the 
energy is stored in it as velocity of upward movement. 

It must therefore continue to move up till its energy of motion 
is expended in compressing the atmosphere, in raising the piston, 
and in friction. If friction did not exist and the piston was indefi- 
nitely light, then the portion of the diagram bed would be equal 
in area to the portion def, that is, the work expended by the ex- 
plosion in giving the piston velocity would be equal to the work 



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144 ^* Gas Engine 

expended by the atmosphere in bringing it to rest again. Once 
at rest the vacuum produced allows the piston to be driven down 
again, this time to give up its energy to the motor shaft. 

As the piston in this engine weighs 116 lbs. the work spent in 
raising it through 13 ft is 116 x 13 = 150*8 ft. pounds; deduct 
this from the total work; and 2010 — 151 = 1859 ft lbs. is the 
energy of motion of the piston. 

The relation between energy, mass and velocity is 



2 

e = energy in absolute units. One foot pound = 32 absolute 
units. 

m = mass in pounds. 

v = velocity in feet per second. 

The velocity is therefore v = * / ^ 

v M 
and 

e = 1859 x 32 = 59488 absolute units. 



m= 116 



*= A /iii5_9488 = 3 2near j y . 

V IIO 



The velocity of the piston at the moment when the explosion 
pressure has been expended and the internal and external pressures 
exactly balance is 32 ft. per second or 1560 ft. per minute; at no 
point of the stroke in any ordinary engine, steam or gas, is such a 
high piston speed possible. This explains the recoil of the engine. 
But this is not the average. The piston has attained 32 feet per 
second after moving through 1 '3 feet ; the time taken to move that 

distance is / = a/ - when / = time in seconds. 

s = space passed through. 
v = velocity, 
and s = 1 *3 feet v = 32 feet 



-v- 



2x13 = 028 second. 
3 2 

The piston has taken 0*28 second to move through the 1-3 
feet ; its average velocity during the action of the explosion is 



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Gas Engines of Different Types in Practice 145 

therefore 4*64 feet per second or 278 feet per minute. This, 
although high, is not greatly in excess of that used in the Lenoir 
and Hugon engines. It is less, indeed, than the average piston 
speed now used in modern compression engines, 300 to 400 feet 
per minute being common. If no cooling by the cylinder occurred, 
the line c df would be adiabatic, and the return line fg would 
coincide with the expansion line df\ the portion of the vacuum 
diagram defis due solely to the energy of the explosion, the part 
dfg is due to the cooling of the gases. If cooling did not act at 
all, the area bed would be greater, and therefore def, which is its 
equivalent, would also be greater, that is, the vacuum produced 
would be greater if no cooling whatever existed. 

The theory of its action generally held at the time of M. Tresca's 
experiments seems to have been as follows : 

The work of the explosion consists simply in pushing up the 
piston and filling the space behind it with flame, which flame is 
cooled by contact with the cylinder, and a vacuum results. The 
flame is considered as analogous to steam, and the cooling as 
similar to condensation as in the Newcomen engine. The inven- 
tors of the engine seem to share this erroneous idea ; certainly 
M. Tresca did, as in his report upon the engine he says : * There 
is, therefore, between the older machines and the new one this 
difference of principle, that the pressure in the cylinder can never 
descend below the atmospheric during the upward stroke. The 
negative force of the atmospheric pressure, useless as it was, be- 
comes utilisable. . . .' He clearly considered that the pressure 
during the upward stroke was expended only in lifting the piston 
through a certain height, and as soon as it fell to atmosphere the 
piston stopped and the cooling caused a vacuum, the work being done 
by the falling of the piston and the pressure of the exterior air. 
If the cooling really caused the vacuum, the diagram would be 
quite different ; instead of the pressure touching atmosphere at the 
point d, it would not touch till the point t at the end of the stroke. 
The pressure would then abruptly fall to f, and the piston would 
return. M. Tresca observed that the pressure did fall below 
atmosphere before the end of the stroke, but he considered it as a 
defect. * In reality the piston rises in virtue of the swiftness ac- 
quired to beyond the position at which there would be equilibrium 



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146 The Gas Engine 

between the interior and exterior pressure. But that one small 
loss of power is amply compensated for by the atmospheric power 
of the downward stroke.' 

The very principle of the engine really depends upon this fall 
of pressure which was considered by M. Tresca a defect ; it is the 
only way to store up the power of the explosion so that it may be 
available on the downward stroke. If the pressure did not fall, 
the piston would require to be projected 10-5 feet into the air to 
absorb the energy of the explosion in its mass alone ; by the fall 
of pressure it is absorbed with the smaller movement of i-8 feet 
The only part of the diagram due to cooling is the part dfg, not 
more than one- fifth of the total area representing work done by 
the engine. 

The superior economy, it is evident, cannot be altogether due to 
greater piston velocity ; the piston velocity, although considerable, 
is not superior enough to that of Lenoir and Hugon to account 
for all the difference. There must exist other points of dissimi- 
larity. In the Lenoir type of engine the strokes were numerous 
and the gas consumed per stroke on the whole smaller than in 
Otto and Langen engines of equal power : the latter used few 
strokes but large cylinders ; proportionally the cooling surface 
exposed was thus diminished. Then the piston is at rest until 
the explosion puts it in motion ; the pressure gets time to rise to 
its maximum before the piston moves and expands the space. 
Maximum pressure is attained at constant volume as required by 
theory ; at the same time the piston and cylinder remain cool be- 
cause of the infrequency of the strokes. The entering charge is 
therefore but slightly heated before explosion, and the explosion 
gives a betier pressure for a smaller elevation of temperature. 

The most potent cause of improvement, however, is great ex- 
pansion : the large cylinders allow an expansion of 10 times the 
volume existing before explosion, and so gain, first by expanding 
to atmosphere, and second by the cooling which follows the further 
expansion. A comparison of the actual diagram with the theo- 
retical reveals some interesting peculiarities which seem hitherto 
to have escaped observation. The maximum pressure on the 
diagram, which is above the true pressure, fig. 35, is 54 lbs. above 
atmosphere, corresponding to a temperature of 1355 absolute. 



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Gas Engines of Different Types in Practice 147 

The mixture exploded contains 1 volume gas and 7 volumes air 
(Oldham gas) ; if all the heat present had been evolved by the 
explosion the pressure should have been 168 lbs. above atmo- 
sphere. At the maximum pressure only 32 per cent, of the heat has 
been evolved, leaving 68 per cent to be evolved during the ex- 
pansion. The line ^is very much above the adiabatic, so much 
so that the curve c d is nearly isothermal, the temperature at d only 
becoming 1305 absolute instead of 733 , which it should be if adia- 
batic. The heated gases are therefore gaining heat from c to d, and 
as the only source is combustion, it follows that the combination 
is not nearly complete at the maximum pressure. The 68 per cent. 




< 



\n 

h 5 

Scale 1 in. = 24 lbs. Diluted mixture, gas z vol., air 12 vols. 
Fig. 36.— Diagram from 2 h. p. Otto and Langen Engine (Clerk). 

of the total heat which has not appeared at the maximum pressure 
is appearing during the expansion. The combustion seems to be 
nearly complete at the point d as the line de behaves as if cooling ; 
if adiabatic, the temperature at/ should be 961 — it is 870 . During 
compression to atmosphere again, the temperature remains con- 
stant at 870 ; the cooling power of the cylinder is equal only to 
preventing increase which would otherwise occur. 

This effect is more evident with a more dilute mixture. Fig. 36 
is a diagram taken by the author from the same engine, but using 

La 



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148 



TJie Gas Engine 



a mixture containing i volume of gas and 12 volumes of air. Here 
the maximum pressure is only 17 lbs. per square inch above atmo- 
sphere. With complete evolution of heat it should be 103 lbs. ; the 
maximum pressure in this case only accounts for 24 per cent, of the 
heat known to be present, leaving 76 percent to be evolved during 
expansion. The diagram affords the most ample proof that the 



-ni 



8o-" 



60- ' 



iovPAImoIuIb 




60 



30 



40 50 60 70 

Percentage of stroke. 



90 



Fig. 37.— Otto and Langen Engine. Free Piston. 

combustion is proceeding, the falling line shows a steady increase 
of temperature to the very end of the stroke. The temperatures 
are marked upon the diagram at the successive points ; taking the 
temperature at the point b as 290 absolute, the points c, d, e,f,& h 
are respectively 780 , 936 , 1092 , 1107 , 1160 , and 1225 , show- 
ing a steady increase throughout the whole expansion line, right 



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Gas Engines of Different Types in Practice 149 

to the end of the stroke. The consumption of gas per indicated 
HP rises very much in consequence, amounting to about 37 cubic 
feet per I HP hour. The power at the same time falls, so that 
the 30 explosions per minute are required to keep the engine going 
without load at 53 revolutions per minute. The cooling during 
compression is so slow that the temperature falls only from 1225 
to 967 , from the point h to k. All the published diagrams examined 
by the author show this peculiar effect. Fig. 37 is a diagram pub- 
lished by Mr. F. W. Crossley. Taking 80 lbs. as the maximum pres- 
sure, which seems somewhat higher than is warranted by the dia- 
gram, the oscillation of the indicator has been so excessive, the cor- 
responding temperature is 1873 absolute : the expansion line cd if 
adiabatic would give at the point d a temperature of 1090 , the 
actual temperature is 1044 . Within the limits of error they may 
be considered the same ; there is therefore combustion going on 
from c to d also. At the point e the temperature is 788 ; if adia- 
batic it should be 667 . It is quite evident that the whole of this 
expansion curve is above the adiabatic ; in the earlier part of the 
diagram the oscillation causes uncertainty, but in the latter part 
the measurement is true enough. 

The compression line ^is almost isothermal, 788°at <?, cooling 
to 737 at g. 

Fig. 38 is a diagram by Releaux taken from Schottler. 

It is manifestly wrong, as the vacuum part is much too small 
and the maximum temperature is higher than has ever been ob- 
tained by any explosion of gas and air, but if taken as relatively 
correct the expansion line is much above the adiabatic 

From his study upon the explosion of gas and air mixtures in 
closed vessels, the reader will be prepared to find that only a 
portion of the total heat present is evolved by explosion in any 
gas engine. That is, the explosion maximum pressure never accounts 
for the whole heat present as inflammable gas ; a portion is in some 
manner suppressed and is not evolved till long after the moment 
of complete explosion. Combustion is not completed till con- 
siderably after the completion of explosion. 

He will be unprepared, however, for such diagrams as figs. 35 
and 36, where the maximum pressure represents only 0*32 and 0*24 
of the heat present, and o-68 and 076 are evolved during the forward 



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150 



The Gas Engine 



stroke while the pressure is falling. The explanation is simple. 
The case is quite different from that of the closed vessel or where 
the piston is connected to a crank. As soon as the pressure of 
the explosion becomes great enough, the piston at once moves out 
and prevents further increase of pressure. The slower the rate at 
which the mixture inflames, the greater will be the apparent sup- 
pression of heat ; thus the mixture i volume gas 7 air takes, in the 
closed vessel, o # o6 second to complete the explosion, but before this 




Fig. 38.— Otto and Langen. 

time has elapsed the piston is in rapid motion reducing the pressure 
before complete explosion. To get the maximum pressure it 
would be necessary to prevent it from moving till the explosion 
was complete. The weaker mixture takes 0*25 second to complete 
the explosion, and so in diagram, fig. 36, the temperature actually 
rises throughout the whole stroke. 

A heavier piston would be longer in starting under the pressure 
of the explosion and would so allow a high pressure to be attained 



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Gas Engines of Different Types in Practice 151* 



-ritiE risTcrT 



with a given mixture. This explains Mr. Crossley's remark in reading 
his paper, that heavy pistons gave a more economical result than 
light ones. 

Gittes Engine. — The great 
success of the Otto and Lan- 
gen engine occasioned many 
attempts to improve upon 
it Its merits and its faults 
were equally evident The 
recoil of the engine at every 
stroke was exceedingly trouble- 
some, and the noise of the rack 
and clutch could be heard at 
a long distance. Gilles of Co- 
logne invented an engine in- 
tended to retain the economy 
while reducing the noise. In 
it there are two pistons, one 
free, the other connected to the 
crank in the usual way. The 
free piston being at the bottom 
of its stroke and close to the 
crank piston, the latter moves 
a portion of its stroke, taking 
in the explosive charge ; at a 
suitable position ignition oc- 
curs and the free piston is 
driven in one direction while 
the other completes its out- 
stroke. A vacuum is pro- 
duced between the pistons, 
and the free piston rod being 
gripped by a clutch is kept in 
its extreme position till the 
main piston returns under the 
pressure of the atmosphere. FlG 39 ._ G Ules Engine. Free Piston. 
The clutch is then released and 
the free piston falls, expelling the exhaust gases. Fig. 39 is a 




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t$2 The Gas Engine 

section of the engine. It is unnecessary to give further descrip- 
tion, as the engine was not so economical or so simple as the 
earlier one. 

Type II. 

In engines of this kind compression is used previous to 
ignition, but the ignition is so arranged that the pressure in the 
motor cylinder does not become greater than that in the 
compressing pump. The power is generated by increasing 
volume at a constant pressure. Engines of Type II. are there- 
fore : 

Engines using a mixture of inflammable gas and air compressed 
before ignition and ignited in such a manner that the pressure 
does not increase, the power being generated by increasing 
volume. 

These engines are truly slow combustion engines ; in them there 
is no explosion. 

The most successful engine of the kind is an American invention; 
although proposed in i860 by the late Sir William Siemens, it was 
never put into practicable workable shape till 1873, when the 
American, Brayton of Philadelphia, produced his well-known 
machine. 

Messrs. Simon of Nottingham introduced it into this country in 
1878. They added one thing only of doubtful utility — that is, the 
use of steam raised in the water jacket as auxiliary to the flame in 
the motor cylinder. 

Brayton Engine, — In this engine there are two cylinders, com- 
pressing pump and motor. The charge of gas and air is drawn 
into the pump on the out-stroke and compressed on the return 
into a receiver ; the pressure usual in the receiver varies from 60 
to 80 lbs. per square inch above atmosphere. The motor cylinder 
lakes its supply from the receiver but the mixture is ignited as it 
enters, a grating arrangement preventing the flame from passing 
back; the mixture, in fact, does not enter the motor cylinder at all ; 
what enters it, is a continuous flame. At a certain point the supply 
of flame is cut off and the piston, moving on to the end of its stroke, 
expands the volume of hot gases to nearly atmospheric pressure 
before discharge. 



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Gas Engines of Different Types in Practice 153 

Fig. 40 is an external view of the engine. Figs. 41 and 42 are 
sections of the motor and pump cylinders. The action is as fol- 
lows : — The engine is single acting, receiving one impulse for every 
revolution ; like all gas engines it depends upon the energy stored 
up in the fly wheel to carry it through those parts of its cycle 




40. — Bray ton Petroleum Engine. 



where the work is negative. The two cylinders are inverted and 
are attached to a beam rocking beneath them, by connecting rods. 
The beam is prolonged and connected to the crank above it by a 
rod ; both cylinders are single-acting and the pistons are of the 
trunk kind. Both pump and motor cylinders are of the same 



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1 54 The Gas Engine 

diameter, but the pump is only half the stroke of the motor. The 
valves are actuated from a shaft running at the same rate as the 
main shaft and driven from it by bevel wheels. There are four 
valves, all of the conical seated kind — two upon the motor, 
admission and discharge, two upon the pump cylinder, admission 
and discharge. The admission and discharge valves upon the 
motor are actuated from the auxiliary shaft by levers and cams, so 
is the pump inlet The pump discharge valve is automatic, rising 
at the proper time by the pressure of compression. During the 
down-stroke the pump takes in the charge of gas and air, forcing 
it on the ur>stroke into the receiver. From the receiver it is led to 
the power cylinder, passing by the inlet valve through a pair of 
perforated brass plates with wire gauze placed between them. 
Through this diaphragm a small stream of mixture is constantly 
passing into the motor cylinder; before the engine is started, a 
plug is withdrawn and the current lighted ; a constant flame is 
therefore burning under the diaphragm. The mixture enters the 
cylinder through this flame, lighting as it enters ; at all times 
during the exhaust part of the stroke, as well as the admission, the 
stream of entering mixture, from the receiver, keeps up a small 
constant flame which is augmented at the beginning of the stroke, 
so as to fill the cylinder entirely, when the admission valve is 
opened When the admission valve is closed, the bye-pass keeps 
the flame fed with sufficient mixture to keep it alight The 
pressure in the cylinder thus never exceeds that in the reservoir 
and the mixture burns quietly without spreading back. 

Figs. 40, 41 and 42. — a is the motor cylinder ; b the pump ; 
the beam and connections require no lettering ; c is the pump 
inlet valve (the pump discharge, which is an ordinary lift valve, is 
not seen in fig. 42, but is lettered d in fig. 40) ; e the motor inlet ; 
f the igniting plug which is withdrawn when the flame is to be lit 
before starting the engine (see fig. 82) ; g is the grating in section 
(see fig. 41); h the exhaust valve; the levers and cams are 
sufficiently indicated on the drawing ; the small pipe and stop- 
cock 1 (fig. 40) communicates at all times with the reservoir and 
supplies the constant flame with mixture. The engine worked 
well and smoothly ; the action of the flame in the cylinder could 
not be distinguished from that of steam, it was as much within 



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Gas Engines of Different Types in Practice 15; 

control and produced diagrams quite similar to steam. The flame 
grating was the weak point ; it stood exceedingly well for a time, but 
if by any accident the gauze was pierced in cleaning, the flame 
went back into the reservoir and exploded all the mixture — the 
engine, of course, pulled up as the constant flame having no supply 





Fig. 41.— Brayton Engine. 
Section of Motor Cylinder. 



Fig. 42. — Brayton Engine. 
Section of Pump Cylinder. 



was extinguished. This accident became so troublesome that 
Mr. Brayton discontinued the use of gas and converted his engine 
into a petroleum engine. The light petroleum was pumped upon 
the grating into a groove, filled with felt, the compressing pump 



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156 



The Gas Engine 



then charged the reservoir with air alone. The air in passing 
through the grating carried with it the petroleum, partly in vapour, 
part in spray; the constant flame was fed by a small stream of air. 
The arrangements were, in fact, precisely similar to the gas engine, 
except in the addition of the small pump and the slight alteration 
in the valve arrangements. The difficulty of explosion into the 
reservoir was thus overcome, but a new difficulty arose — the 
cylinder accumulates soot with great rapidity and the piston 
requires far too frequent removal for 
cleaning. The petroleum pump is an 
exceedingly clever little contrivance ; 
fig. 43 shows its details. The amount 
of petroleum to be injected at each 
stroke is so small that an ordinary force 
pump with clack valves would be un- 
certain. Bray ton gets over this difficulty 
by substituting a slide valve driven from 
the eccentric. 

The plunger of the pump is no larger 
than a black-lead pencil, yet it dis- 
charges any quantity, from a single drop 
per stroke up to full throw, with un- 
erring certainty. The plunger also is 
driven from an eccentric. Both eccen- 
trics are in one piece and rotate on the 
end of the auxiliary shaft, driven by a 
pawl when the engine is in motion ; to 
allow of starting, the pump can be 
moved by a hand-crank independently. 
To start, the air reservoir is filled, if not 
already full, by turning the engine round 
by hand ; the plug f is then withdrawn 
and a little petroleum thrown upon the diaphragm by a few turns 
of the pump. The cock i on the small pipe is then opened and 
a stream of air flowing from the reservoir vaporises the petroleum ; 
it is lit at g, and the flame having enough air for combustion retreats 
to the grating and remains burning within the cylinder. The plug 
is then inserted, the starting cock opened, and the engine starts. 




Fig. 43. 
Bray ton Petroleum Pump. 



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Gas Engines of Different Types in Practice 157 

The flame remains alight during the whole time the petroleum 
continues to be supplied. 

The valves act well and the motor cylinder does not suffer 
from the action of the flame so long as it is kept reasonably 
clean. If the soot, however, is allowed to accumulate, it speedily 
cuts up. 

Diagrams and Gas or Petroleum Consumption. — Prof. Thurston 
of the Stevens Institute of Technology tested a Brayton gas engine 
in New York in the year 1873. 

The following extracts are from his report : 

1 The operation of the engine is precisely similar in the action 
of the engine proper and in the distribution of pressure in its 
cylinder, to that of the steam engine. The action of the impelling 
fluid is not explosive as it is in every other form of gas engine of 
which I have knowledge. 

* Upon the opening of the induction valve, the mixed gases 
enter, steadily burning as they flow into the cylinder, and the 
pressure from the commencement of the stroke to the point of cut 
off, as is shown by the indicator diagrams, is as uniform as that 
observed in any steam engine cylinder. The maximum pressure 
exerted during my experimental trial, and while the engine was 
driving somewhat more than its full rated power, was about 75 lbs. 
per square inch at the beginning of the stroke, gradually dimin- 
ishing to 66 lbs. per square inch at the point of cut-off, where 
the speed of the piston was nearly at a maximum, and then de- 
clining in accordance with the law governing the expansion of 



' Complete combustion is insured by thorough mixture. This 
is accomplished by taking the illuminating gas and air, in proper 
proportion, into the compressing pump together, and the mixture 
here made becomes more intimate in the reservoir, and in its pro- 
gress towards the point at which it does its work. The constantly 
burning jet already described insures prompt ignition on entering 
the cylinder. 

'. . . the engine rated at 5 HP developed, as a maximum, 
rather more than its rated power. Its mean power during the test, 
as determined by the dynamometer, was 3*986 HP, the indicator 
showing at that time 8*62 HP developed in the cylinder. The 



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158 



The Gas Engine 



amount of gas consumed averaged 32*06 cubic feet per indicated 
HP per hour. 

'The excess of indicated over dynamometric HP is to be 
attributed to the work of driving the compressing pump and to the 
friction of the machine. 

4 The greater portion of this appears both in debit and credit 
side of the account, since, although expended in the compressing 
pump, it is restored again in the driving cylinder.' 

The consumption of 32-06 cubic feet per horse hour is incor- 
rect ; it is obviously unfair to include the pump diagram in the 
gross power. The author has tested an engine of similar con- 
struction and dimensions ; he finds the friction of the mechanism 




Max. press. 68 lbs. per sq. in. 
Flli. 44. 




Fig. 45. - Diagrams from Bray ton's Gas Engine. 

to be about i -horse ; adding this number to the dynamometric 
power of Prof. Thurston, the legitimate indicated power may be 

taken as 5 HP, the consumption is therefore — -^3—9 =55-2; 

and the gas per brake HP per hour is -*- 1 ,-° =69*3. These 

numbers, although showing improvement upon the Lenoir and 
Hugon, prove that the engine was much inferior in economy to 
the Otto and Langen engines. 

Mr. H. McMutrie, Consulting Engineer at Boston, took dia- 
grams from an engine of similar dimensions which confirm these 
results. Fig. 44 is the diagram taken with full load, fig. 45 the 
diagram from the motor with no load on, the power being just 
sufficient to overcome friction and pump losses. 



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Gas Engines of Different Types in Practice 1 59 



Full Load Diagram. 



Area of piston . 
Speed of piston . 
Mean pressure . 
Pressure in reservoir . 
Initial pressure in cylinder 
Gross power developed 



No Load Diagram. 



Speed of piston . 

Mean pressure 

Friction and other resistance 

Net available power . 



50*26 sq. ins. 
180 ft. per min. 
33 lbs. per sq. in. 
754 lbs. persq. ii 
68 lbs. per sq. in. 
9 HP. 



180 ft. per min. 
18 lbs. per sq. in. 
4 87 HP. 
9 - 487 = 413 



This power agrees closely with the actual determination by 
dynamometer. 

The author has made a careful trial of a Bray ton petroleum 
engine rated at 5 -horse. The engine was made by the * New York 
and New Jersey Ready Motor Company ; ' it was sent to Glasgow 
and the following test was made at the Crown Ironworks on the 
21st and 22nd February, 1878. The motor cylinder is 8 inches 
in diameter and the stroke 1 2 inches ; the pump cylinder is also 
8 inches diameter but the stroke is 6 inches. 

Diagrams were taken from both pump and motor by a well- 
made Richards' indicator. At the same time the dynamometer 
was applied to the fly wheel fully loading the engine, readings were 
taken at regular intervals. The revolutions were recorded by a 
counter. The petroleum used was measured in a graduated glass 
vessel . 

The results are as follows : 

Test of Brayton Petroleum Engine. {Clerk.) 

Petroleum consumed during one hour i '378 gallons. 

Mean speed of engine 201 revs, per min. 

Mean dynamometer reading 4 26 HP. 

Mean pressure, power cylinder . -3' lbs. persq. in. 

Mean pressure, air pump 27 6 lbs. persq. in. 

Piston speed, motor 201 ft. per min. 

Piston speed, pump 100 5 ft. per min. 

Power indicated in motor 949 HP. 

Power indicated in pump 410 HP. 

Available indicated power 5 39 



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l6o 



Tlie Gas Engine 



The power by the dynamometer is 4*26-horse ; therefore the 
mechanical friction of the engine is 5*39— 4*26=113 horse. 



Consumption of petroleum 
Consumption of petroleum 



0-255 galls, per I HP per hr. 
0323 galls, per actual HP per hr. 



Figs. 46 and 47 are diagrams from the motor and pump, which 
are fair samples of those taken. It will be observed that consider- 
able throttling occurs in entering the motor cylinder ; the pump 
pressure is higher than the reservoir pressure, and the motor pres- 
sure is lower, so that a double loss has been incurred. The prin- 
ciple of the engine is so good that the author anticipated better 
results. Great improvement could be obtained by reproportioning 



45 


&7 


46 


U8 


60 


3/ 


S3 


12 


// 


^L> 



Mean pressure 30*2 lbs. per sq. in. 8 ins. dia. cylinder. Stroke 13 ins. 200 revs, per min. 
Fig. 46. — Bray ton Petroleum Engine. Motor Cylinder. 




Mean pressure 27*6 lbs. per sq, in. 8 ins. dia. cylinder. Stroke 6 ins. 200 revs, per min. 
Fig. 47. — Brayton Petroleum Engine. Pump Cylinder. 

the valves and air passages ; they are in this engine much too small 
and cause needless resistance and loss. The maximum pressure 
in the motor cylinder is 48 lbs. per square inch, which remains 
steadily till the inlet valve shuts at four-tenths ot the stroke : the 
pressure then slowly falls as the gases expand, the exhaust valve 
opening at about ten pounds per square inch above atmosphere. 
The average available pressure upon this diagram is 30*2 lbs. 



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Gas Engines of Different Types in Practice 161 

per square inch. The air pump shows a maximum pressure of 
65 lbs. per square inch, the reservoir pressure being 60 lbs. The 
average resistance is 27-6 lbs. per square inch ; as the pump is half 
the stroke of the motor and equal to it in area, the pressure to be 

deducted is 27 — = 13*8 and 30*2 — 138 = 16-4. The actual 
2 

available pressure actuating the engine is therefore only 16*4 lbs. 

per square inch. The effect of the clearance in the pump cylinder 

is noticeable upon the diagram ; the air inlet valve does not open 

till one-tenth of the down stroke is completed. 

The theoretic efficiency of this type, with a maximum tempera- 
ture of 1600 C, compression of 60 lbs. per square inch above 
atmosphere, and motor cylinder of twice the pump volume, is 0*30 ; 
the efficiency of the gas in the mixture commonly used, 1 volume gas 
7 volumes of air, is 0*40 (p. 113) ; so that if the conditions of loss 
by cooling are no worse than in the author's explosion experiments, 
and the diagram appeared perfect, the actual indicated efficiency 
would be 0*30 x 0*40 = o*i2. That is, the engine should convert 
12 per cent of the heat it gets as gas or petroleum into indicated 
work. But the diagram is imperfect in many ways. Using the mix- 
ture it does, the diagram should show a maximum temperature of 
1600 C. at least ; in reality the highest temperature is only 840 C. 
The flame is entering the cylinder at an actual temperature of 
1600 C. during the whole period of admission, but the convec- 
tion has so greatly increased by the mixing effect of the entering 
current that greatly increased cooling results ; accordingly, when the 
gases are fully admitted and the inlet valve is closed, the gases have 
only a temperature of 840 C. instead of 1600° C. After admis- 
sion ceases, the expansion line from 45 lbs. to 10 lbs. pressure is far 
above the adiabatic, indeed it is isothermal, the combustion is 
proceeding and the small igniting flame also is helping to sustain 
the temperature. 

It is therefore quite evident that the loss of heat is much greater 
than that occurring during explosion in equal time. The correction 
of the theoretic efficiency indicated by the author's closed vessel 
experiments is insufficient, 0*12 is much above the actual effici- 
ency. Taking the heating value of the American coal gas used 
in Prof. Thurston's experiments as 10,900 heat units per unit weight 

M 



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1 62 TJie Gas Engine 

of gas burned, and one pound of it as measuring 30 cubic feet, 
then as the engine used 55 cubic feet per IHP per hour, itb 
efficiency is 0*07 1 ; that is, it converts 7 'i per cent, of the heat given 
to it into work. 

This is a poor result for a cycle having so high a theoretic 
efficiency, and in the author's experiments with petroleum it is 
even worse. 

The sp. gravity of the petroleum was 0*85, therefore the weight 
of one gallon is 8*5 lbs. As 0*255 gallons are burned per indi- 
cated horse power per hour, this amounts to 8*5 xo*255=2 , i61bs. 
of liquid fuel per IHP per hour. One pound gives out 1 1,000 
heat units, and for one horse power for one hour 1424 units are 
required ; the actual indicated efficiency is therefore 

— I42 4 = I42 , 4 - = o*o6 nearly : that is, 6 per cent, of the 

2*io xi 1000 23760 

whole heat given to the engine is accounted for by the power 

developed in the motor cylinder. 

If there were no losses of heat to the cylinder, or losses by 
throttling during the inlet and transfer of the air from the pump 
to the motor or loss of heat from the reservoir to the atmosphere, 
then the efficiency of this type of engine would be 30 per cent. 
These losses in practice reduce it to 6 per cent. The cycle is a 
good one, and under other circumstances is capable of better 
things, but it is quite unsuitable for a cold cylinder engine. Cool- 
ing and undue resistance are the main causes of the great deficit. 

The gases entering the cylinder as flame, in passing through 
the inlet chamber expose a large surface to the action of the water 
jacket; the entering currents also impinge against the piston, 
causing more rapid circulation than ordinary convection. Both 
causes intensify the cooling action of the cylinder walls. In the 
engine tested by the author the communicating pipes and the 
motor admission valve were much too small ; a considerable loss 
of pressure resulted ; although the reservoir pressure was 60 lbs., 
that in the cylinder never exceeded 48 lbs. above atmosphere, 
showing a loss of 12 lbs. per square inch from undue resistance. 
To enable this engine to realise the advantages of its theory con- 
siderable modifications in its arrangements are required. Notwith- 
standing all difficulties it has done much useful work, not the least 



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Gas Engines of Different lypes in Practice 163 

notable being the assistance it rendered to Prof. Draper during his 
investigation on the existence of non- metallic bodies in the sun's 
atmosphere. He used a Bray ton petroleum engine for driving his 
dynamo machine, and he stated in his paper that its ease of starting 
and almost absolute steadiness in driving were of the greatest ser- 
vice to him. In steadiness he states that * it acted like an instru- 
ment of precision.' 




Fig. 48. — Simon Engine. 

Simon Engine.— Messrs. Simon, of Nottingham, introduced the 
Brayton engine to England in a slightly altered form as a gas 
engine. In addition to the ordinary arrangements of the engine 
they attempted to gain increased economy, by causing the waste 
heat passing into the water jacket, and the heat of the exhaust 



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1 64 



The Gas Engine 



gases, to be utilised in raising steam. They would undoubtedly 
have increased the economy of the engine in this manner had 
they not turned the steam so raised into the motor cylinder along 
with the flame. The cooling of the flame which was serious 
enough in the original was thus made worse, and but slight gain 
could result, the loss by cooling being slightly exceeded by the 
increase of volume due to the steam. Fig. 48 is an external view 
of the engine as exhibited at the Paris Exhibition of 1878. a is 
the motor, b the pump, and c the added boiler \ the steam was 
raised in it and the water jacket. With a suitable arrangement 
using the steam in a separate cylinder, doubtless 6 per cent, might 




7 ins. dia. of cylinder ; 240 ft. per min. piston speed. Scale A in. 

Fig. 49.— Diagram from Simon Engine. 

be added to the indicated efficiency of the engine, but it is very 
questionable if the increased complexity does not entirely destroy 
any advantage gained ; it certainly does so in small engines. When 
very large engines come to be constructed the complexity would 
not be so great and it would be well worth while to use waste heat 
in steam raising. The engine, although instructive, did not suc- 
cessfully overcome the difficulties which caused the abandonment 
of the Brayton as a gas engine. Fig. 49 is a diagram from the 
engine which forcibly illustrates the effect of the cooling. 



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Gas Engines of Different Types in Practice 165 



Type III. 

Engines of this kind resemble those just discussed, in the use 
of compression previous to ignition, but differ from them in ignit- 
ing at constant volume instead of constant pressure ; that is, the 
whole volume of mixture used for one stroke is ignited in a mass 
instead of in successive portions. 

The whole body of mixture to be used is introduced before 
any portion of it is ignited ; in the previous type the mixture is 
ignited as it enters the cylinder, no mixture being allowed to enter 
except as flame. In Type III. the ignition occurs while the volume 
is constant ; the pressure therefore rises ; it is an explosion engine 
in fact, like the first type, but with a more intense explosion due 
to the use of mixture at a pressure exceeding atmosphere. 

The most obvious means of applying the method is that sug- 
gested by the Lenoir engine. The addition of a pump taking 
mixture at atmospheric pressure, compressing it into a reservoir 
from which it passes to the motor cylinder at the increased pres- 
sure, seems a simple matter. The igniting arrangements would 
act as in the original. As the gases are under pressure, the piston 
would take its charge into the cylinder in a smaller proportion of 
the forward stroke, and so more of the motor stroke would be 
available for useful effect. The diagram such an engine should 
produce is seen at fig. 15, p. 50; the shaded part is the available 
portion, the other part is the pump diagram. The theoretic effi- 
ciency of such an engine is as good as the type can give. The 
patent list shows that it was the first proposed after Lenoir. Many 
such engines have been attempted and have given very good re- 
sults economically, but the difficulties of detail are considerable, 
the greatest being the necessity for the intermediate reservoir. 
Million's patent 1861 proposes to do this, the present author also 
constructed one of this kind in 1878, and later one was made by 
Mr. Atkinson. The difficulties, however, are too great to allow the 
success of small motors on the plan. 

Mr. Otto, the first to succeed with the free piston engine, was 
also the first to succeed in adapting compression in a reliable 
form. 



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1 66 Tlte Gas Engine 

In the third type are included all engines having the following 
characteristics, however widely the mechanical cycle may vary : 

Engines using a gaseous explosive mixture, compressed before 
ignition, and ignited in a body, so that the pressure increases while 
the volume remains constant. The power is obtained by expan- 
sion after the increase of pressure. 

Otto Engine. — In this gas engine, the first to combine the 
compression principle with a simple and thoroughly efficient work- 
ing cycle, the difficulties of compression are overcome in a strikingly 
original manner. To the engineer accustomed to the steam 
engine, the main idea seems a bold and indeed a retrograde step. 
The early gas engines were moulded more upon the steam engine 
model and were to some extent double acting. The Lenoir and 
Hugon both received two impulses for every revolution, the 
Bray ton was single acting, and the Otto is only half single acting. 
The steam engine in its advance passed from single to double 
acting, and then to four and even more impulses per revolution. 
The gas engine in its progress has in this respect moved backwards, 
beginning with double action and then going back. The gain of 
this arrangement, however, has completely justified the retro- 
gression. 

In external appearance the engine closely resembles a modern 
high pressure steam engine, the working parts of which are of 
somewhat excessive strength ; its motor and only cylinder is hori- 
zontal and open ended ; in it works a long trunk piston, the front 
end of which serves as a guide and does not enter the cylinder 
proper ; the connecting rod communicates between the guide and 
the crank shaft, the side thrust is thus kept off the piston and 
cylinder proper, which become hot. The crank shaft is heavy and 
the fly-wheel a large one ; considerable energy being required to 
take the piston through the negative part of the cycle. The 
cylinder is considerably longer than the piston stroke, so that the 
piston when full in leaves a considerable space into which it does 
not enter. 

Outside the cylinder, running across it at the end of the space, 
works a large slide valve ; it is held against the cylinder face by 
a cover plate and strong spiral springs ; it is driven to and fro by 
a small crank, on the end of a shaft parallel to the cylinder axis, 



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Gas Engines of Different Types in Practice 167 




a 
"St> 



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1 68 The Gas Engine 

and rotating at half the rate of the crank shaft, from which it 
receives its motion by bevel or skew gearing. 

An exhaust valve, leading into the space by a port, is also 
actuated at suitable times from the secondary shaft ; so are the 
governing and oiling gear. 

The single cylinder serves alternately the purposes of motor 
and pump ; during the first forward stroke of the piston, the slide 
valve is in such position that gas and air stream into the cylinder 
from the beginning to the end of the stroke, the charge mixing as 
it enters with whatever gases the space may contain ; the return 
stroke then compresses the uniform mixture into the space, and 
when the piston is full in, the pressure has increased to an amount 
determined by the relative capacity of the space. Meantime the 
slide valve has moved to another position, first closing the admission 
gas and air ports, to permit of the compression, then bringing on a 
cavity in the valve which is filled with flame, when the compression 
is completed. The compressed charge therefore ignites and the 
pressure rises so rapidly that maximum is attained before the piston 
has moved appreciably on its forward stroke (second stroke) ; 
the piston is thus under the highest pressure at the beginning of 
its stroke and the whole stroke is available for the expansioa 

This is the motive stroke. At the end of it, the exhaust valve 
opens and the return stroke is occupied in driving out the burned 
gases, except that portion remaining in the space which cannot be 
entered by the piston. These operations form a complete cycle, 
and the piston is again in the position to take in the charge re- 
quired for the next impulse. 

The cycle requires two complete revolutions, or four single 
strokes. 

First out stroke. Charging cylinder with gas and air. 

,, in „ Compressing the charge into the space. 

Second out stroke. Explosion impelling piston. 

„ in „ Discharging burned gases into atmosphere. 

The regulation of the speed of the engine is accomplished by 
a centrifugal governor, which is arranged to close a gas supply 
valve whenever the speed increases. An explosion is thereby 
missed, and the engine goes through its cycle as usual, but as no 



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Gas Engines of Different Types in Practice 169 




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170 The Gas Engine 

gas is mixed with the air, there is no explosion when the flame 
enters, the compressed air merely expanding, giving back to the 
piston the energy taken during compression. 

When running without load, 8 or even more revolutions maybe 
made between the impulses, at full load 2 revolutions are made per 
impulse. Notwithstanding this irregularity the fly-wheel is so 
large that no variation observable by the eye can be seen while 
watching the engine. 

Fig. 50 is an external elevation of an Otto engine. 

Fig. 51 is a sectional plan, and fig. 52 an end elevation showing 
exhaust valve lever, a is the water-jacketed cylinder, b the piston 
shown full in, c is the compression space or cartridge space as it 
is called by Million; 1 the admission and ignition port, communi- 
cating alternately with the gas and air admission port k, and the 
flame port l in the slide m ; n is the cover holding the slide to the 
cylinder face and carrying in it the external flame for lighting the 
movable one in flame port l. The exhaust valve is of the conical 
seated lift type and is seen at o; it is driven from the shaft p by 
the cam q and the lever r. The other details are clearly shown 
upon the drawing. The ignition valve and governing arrangement 
will be described in a subsequent chapter ; here it is sufficient 
to state that the governor withdraws a cam actuating the gas 
valve s, fig. 52, and so prevents it opening when the piston is 
taking in air. When open, the gas passes the valve, then through 
a row of holes in the valve port k, streaming into the air and mix- 
ing thoroughly with it as it enters the cylinder. To start the 
engine, the flame at t is lighted ; the cock commanding the internal 
flame being properly adjusted, and the gas turned on, a couple of 
turns at the fly-wheel should cause ignition and set the engine 
in motion. The larger engines are provided with a second cam, 
which keeps the exhaust valve open during half of the compression 
stroke and so diminishes the work required to turn round the engine 
by hand. When the engine is started the wheel upon the lever is 
shifted to the normal cam and the compression then returns to its 
usual intensity. 

Diagrams and Gas Consumption. — Dr. Slaby, of Berlin, has 
made a very careful trial of a four-horse power Otto engine at 
Mr. Otto's works, Deutz, in August 1881. 



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Gas Engines of Different Types in Practice 171 




Fig. 52.— Otto Engine (End elevation). 



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172 TJte Gas Engine 

The dimensions of the engine are : 

Diameter of cylinder 171 9 millimetres. 

Stroke 340 millimetres. 

Compression space 477<> cb. centimetres. 

Volume displaced by piston .... 7888 cb. centimetres. 

The compression space is therefore 06 of the volume displaced by 
the piston. The results are briefly as follows : 

Average revolutions during test . . 1567 per minute. 

Power indicated in cylinder .... 504 horse. 

Power by dynamometer 4 "4 horse. 

Gas consumed in one hour .... 142*67 cb. ft. 

Gas consumed in one hour by igniting flames . 275 cb. ft. 

Gas consumption per IHP per hour . 28 3 cb. ft. 

Gas consumption per effective HP hour . . 32 4 cb. ft 

The composition of the gas used at the Gasmotoren-Fabrik, 
Deutz, is given as — 

Volumes. 

Marsh gas, CH 4 34 '4 

Ethylene, C 2 H 4 3 5 

Hydrogen, H 56*9 

Carbonic oxide, CO 5*2 

100 *o 

and 1 cubic metre of it weighs 0*404 kilograms. One pound 
weight of it therefore measures 39*6 cubic feet. Deducting the 
latent heat of steam produced, 1 pound weight evolves heat enough 
to raise 12,094 lbs. of water, through one degree Centigrade. It 
evolves 12,094 heat units. From this value, and the experimental 
determination of the heat leaving the engine by way of the water 
jacket, Dr. Slaby calculates the disposition of 100 heat units given 
to the engine as follows : 

Work indicated in cylinder 16 'o 

Heat lost to cylinder walls 51 "o 

Heat carried away by exhaust 31*0 

Heat lost from engine by conduction and radiation . .2-0 

100 'o 

The actual indicated efficiency of the engine is therefore 16 
per cent, or ot6. 

The temperature of the gases expelled during the exhaust 
stroke was determined by carefully protecting the exhaust pipe 



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Gas Engines of Different Types in Practice 173 

from loss of heat by non-conducting material, and then seeing 
whether zinc or antimony would melt in it. Zinc melted but 
antimony did not ; as the melting point of zinc is 423 C, and the 
antimony melting point is 432 C, the temperature of the exhaust 
gases is given with great accuracy as between these two tempera- 
tures. The average composition of the mixture is given as 1 voL 
coal gas to 1373 vols, of air and other gases. Here Dr. Slaby is 
plainly in error, as his own figures conclusively show. The volume 
of coal gas taken into the engine at each stroke as measured 
by the gas meter is given as 859 cubic centimetres, the total 
volume swept by the piston of the engine per stroke is 7888 cubic 
centimetres, the volume of the compression space 4770 cubic 
centimetres. Now if the gas be introduced into the cylinder 
^rhile it is filled completely, space included, with cold gases, at 
the same temperature as the gases when measured by the meter, 
this figure is correct enough. But the gases are not so introduced, 
the space is already filled with exhaust gases at a temperature of 
about 400 C. by Dr. Slaby's own determination ; this volume 
must therefore be calculated to atmospheric temperature before 
an approach to the true ratio can be obtained Taking atmo- 
spheric temperature at 17 C, then 4770 cubic centimetres of 
burned gases at 400 C. becomes reduced to 2055 cubic centi 
metres at 17 C; that is, the total charge will consist of 859 cubic 
centimetres of coal gas, 7029 cubic centimetres of air, and 2055 
cubic centimetres of burned gases from the previous explosion. 
The ratio is 

coal gas 859 1 

air and burned gases 7029 + 2055 ~" 10*5 

The composition of the charge is more correctly represented 
as 1 vol. of gas to 10-5 vols, of air and other gases. Even here, 
however, the dilution is overstated, as it is assumed that the 
piston has taken in the charge at full atmospheric temperature 
and pressure. But there is some throttling in passing through the 
admission valve and port, and also some heating of the air by 
striking the piston and cylinder walls. Professor Thurston, in 
experiments to be described later on, proves this to be the case, 
and shows that the charge is even stronger than has been 
calculated. 



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1 74 Tfie Gas Engine 

It has been already proved that in this type of engine, ex- 
panding after compression and explosion to the same volume as 
existed before compression, the theoretic efficiency is independent 
of the temperature of the explosion or the temperature existing 
before compression, and depends only upon the volume before and 
after complete compression. As the ratio of compression space 
to volume swept by the piston is o*6 to i, the volume before 
compression is r6, volume after compression o-6. 

The theoretic efficiency is (p. 53) e = j — l- c j ' 

and v c is the compression volume, and v the volume before com- 

. , . /o-6\ '** / 1 V**; 

pression ; in this case e= 1 — ( —1 or 1 — ( ——J ' 

here e = 0-33. 

That is, if all the heat were given to the engine at the moment 
of complete explosion at the beginning of the stroke, and no heat 
were lost to the cylinder during the expansion to the original 
volume, then 33 per cent, of that heat would be converted into 
indicated work. But the author's explosion experiments give the 
factor necessary for correcting this theoretical number (p. 113). 
Taking the mixture of 1 gas to 10 vols, air as nearest, the 
efficiency of the gas in it is 0*46 ; that is, during the time of the 
forward stroke, taken as 0*2 sec, 1 vol. of gas is required to pro- 
duce and keep up a pressure which 0-46 vol. would suffice for if 
it was all applied to heating and no loss by cooling. 

The actual indicated efficiency of the engine using this 
mixture and this expansion and compression should be 0*33 x 
0-46=0-152 nearly. That is, the engine should convert 15-2 per 
cent, of the heat given to it into work. Dr. Slaby's number, found 
by experiment, is 16 per cent. The numbers are exceedingly 
close. 

The mechanical efficiency of the engine is high, the ratio of 
dynamometric to indicated power being 87 to 100, and the friction 
of the engine only 064 horse 



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Gas Engines of Different Types in Practice 175 



Professor Thurston's Experiments on a 6 HP Otto 
Engine. 

Dr. Slaby's experiments are exceedingly complete, but Pro- 
fessor Thurston in America has made even more extended 
measurements. 

Messrs. Brooks and Steward made the trials under the direc- 
tion of Professor Thurston, at the Stevens Institute of Technology, 
Hoboken. The dimensions of the engine are as follows : 

Diameter of cylinder 8*5 ins. 

Stroke 14 ins. 

Capacity of compression space 38 per cent, of total cylinder 
volume. 

Not only was the gas entering the engine measured, but at the 
same time the air required was measured through a 300 light 
meter. So far as the author is aware, this is the only set of 
experiments in which this was done ; it is by far the most accurate 
way of getting the true proportions of the explosive mixture. 

The temperature of the exhaust was measured by a pyrometer, 
and the power determined, both by indicator and dynamometer ; 
at the same time the heat passing into the walls of the cylinder 
was determined by measuring the water heated and estimating 
the loss by radiation and conduction.. 

The total number of revolutions during the various tests were 
taken by a counter. Many trials were made under varying con- 
ditions of load and mixture used. The following is the best full- 
power trial, giving the most economical results : 

Average revolutions during test 158 per minute. 

Power indicated in cylinder 9/6 horse. 

Power by dynamometer 8'i horse. 

Gas consumed in one hour 235 cb. ft. 

Gas consumption per IHP psr hour .... 24-5 cb. ft. 

Gas consumption per effective HP per hour 29*1 cb. ft. 

An analysis of the gas used during the trials made by Thomas 
B. Stillman, Ph.D., is as follows : 



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176 



T/ie Gas Engine 



Hydrogen, H 

Marsh gas, CH 4 . 

Nitrogen, N 

Heavy hydrocarbons, C 2 H 6 , &c. 

Carbonic oxide, CO . 

Oxygen, O . 

Water vapour and impurities (H a O, COj, H 2 S) 



39'5 
37*3 
82 
66 
43 
i*4 

ioo'o 



One cubic metre of this gas weighs o*6o6 kilograms. One 
pound weight of it therefore measures 26*43 cubic feet. One 
pound when completely burned evolves heat enough to raise 9070 
lbs. water through i°C. 

The air necessary to supply just enough oxygen for the 
complete combustion of 1 vol. of this gas is 5-94 vols. 

From these values and experiments upon temperature of the 
exhaust gases, Professor Thurston estimates the disposition of 100 
heat units by the engine as follows : 

Work indicated in cylinder 17*0 

Heat lost to cylinder walls 52*0 

Heat carried away by exhaust gases 15-5 

Heat lost from engine by conduction and radiation . 15*5 

IOO'O 

The actual indicated efficiency is therefore 17 per cent. 

The number showing the proportion of heat passing into the 
water jacket is also very nearly Slaby's, but the amount expelled 
with the exhaust is much understated. The amount lost by radi- 
ation is overstated. 

The temperature of the exhaust gases, as determined by a 
pyrometer placed in the exhaust pipe, varies in the experiments at 
full load from 399 C. to 432 ° C, thus practically coinciding with 
Slaby. The ratio of air to gas was found, by actual measurement 
of both, to be about 7 to 1 when the engine was working most 
economically. Although with better gas the ratio would be 
slightly increased, yet it could not equal that usually given for the 
Otto engine, 10 to 1 or thereabouts. 

The ratio is commonly obtained from a measurement of the 
gas consumption alone, the air being reckoned as the volume of 
the piston displacement, less the measured amount of gas. This 
is not an accurate method, for the reason already stated. 



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Gas Engines of Different Types in Practice. 177 

If the mixture filling the cylinder mingles with the burned 
gases filling the compression space, then the average composition 
of the charge is 1 voL coal gas to 9*1 vols, of other gases. 







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178 The Gas Engine 

Fig. 53 is a fair sample of the diagrams obtained during Pro- 
fessor Thurston's tests while the engine was giving full power. 
The piston while moving from the point 1 to the point 2 takes 
in the charge ; the pressure in the cylinder falls below atmo- 
SDhere as the piston approaches the end of its stroke. This is 
due to the resistance of the valve port to entering air and 
gas. The piston returns from 2 to 5 (1st in-stroke) compress- 
ing the charge, the pressure increasing to atmosphere at the 
point 3, the compression being complete at the point 5 ; the 
ignition then occurs, and the pressure and temperature rapidly 
rises as the explosion progresses; the temperature does not 
attain its maximum till the piston has moved forward a little and 
has reached the point 6. From that point to 7, when the ex- 
haust valve opens, the expanding line is as nearly as possible 
adiabatic. The temperatures are marked at each point of the 
diagram. The return stroke from 2 to 1 discharges the products 
of combustion. This is the second in-stroke, completing the 
cycle and leaving the engine in position to again take in the 
charge. 

The diagram shows the whole changes occurring during two 
complete revolutions of the machine while fully loaded. Fig. 54 
shows what occurs when the governor acts, when the engine is at 
less than full load. The smaller diagram, b, is the normal one, 
and the larger, a, the intermittent one ; the gas has been com- 
pletely cut off for several strokes, and so the hot burned gases in 
the compression space have been completely discharged and re- 
placed by pure air at a temperature not far removed from atmo- 
spheric ; the explosion then causes a higher pressure by nearly half 
an atmosphere, although the maximum temperature is less than in 
the usual case. 

The temperature of the charge before explosion being less, a 
smaller increase is required to produce a given increase of pressure. 
Professor Thurston calculates that the heat accounted for by the 
diagram is 60 per cent, of the total heat supplied to the engine \ 
the deficiency he attributes to the phenomena of dissociation, 
which prevents the complete evolution of the heat at the highest 
temperature, but permits further combustion when the temperature 
falls. The amount of gas required to run at full speed, 166 revo- 



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Gas Engines of Different Types in Practice 179 

lutions per minute without any load, was found to be from 50 to 
70 cubic feet per hour. 




Other tests of Otto Engine. —The experiments of Dr. Slaby and 
Professor Thurston upon the Otto engine are by far the most 
complete which have yet been made to the author's knowledge. 



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180 The Gas Engine 

Some tests given in Schottler, however, will be quoted. A four 
HP engine was found to consume as a best result 3 2 -4 cubic 
feet of gas per brake HP per hour in Altona, giving at the time 
3-96 HP on the dynamometer. Another consumed 337 cubic 
feet per brake HP per hour in Hanover, giving 495 HP on 
the dynamometer; to drive the last engine at 160 revolutions per 
minute without load required 41*3 to 43*4 cubic feet of Hanover 
gas. 

A two-horse engine, tested by Erauer and Slaby, Berlin, gave 
a '28 brake HP, using 35 3 cubic feet per brake HP per hour. 

In this country the coal gas in common use is of higher heat- 
ing value than that used on the Continent and in America ; ac- 
cordingly the gas required per HP is less, but the efficiency is 
almost identical. 

Experiments made upon an 8 HP Otto engine by the Philo- 
sophical Society of Glasgow in 1880, shewed a consumption of 
22 cubic feet of Glasgow gas per indicated HP, giving 9 HP upon 
the dynamometer, and 28 cubic feet per dynomemetric horse. 

Experiments made at the Crystal Palace Electrical Exhibition, 
in 1881, with a 12 HP engine gave a maximum brake power of 
i8'3 HP, with a gas consumption of 237 cubic feet per IHP, and 
29*1 cubic feet per brake HP. With a two-horse engine, 2*87 
brake horse was obtained upon 33*4 cubic feet per horse hour, 
and 27-9 cubic feet per indicated horse hour. 

The consumption running without load does not seem to have 
been taken in these tests. 

The author has taken the consumption of a two-horse engine 
running without load in London, at 160 revolutions per minute, as 
32 cubic feet per hour, and a 3*5 horse engine without load at 
166 revolutions per minute as 43 cubic feet per hour. 

The Messrs. Crossley give the following as the results with 
their new Otto twin engine rated at 12 HP : 

Power by d\ namometer 23 horse. 

Power indicated in cylinders . . .28 horse. 

Gas consumption per indicated HP . . 20 cb. ft. per hour. 

Gas consumption per effective HP . 24^3 cb. ft per hour. 

Total consumption at full power .... 560 cb. ft. per hour. 
Total consumption when running without load at 

160 revs, per minute 100 cb. ft. per hour. 



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Gas Engines of Different Types in Practice 181 






o 



'I 






■ ■ 3 " 
I 

• .C 3 ' 

« K I ~ h ^ & 



I g ^ 1 1 a a 

ca a: cq ,5 3 3 




ctf 

o 

c 

'& 

c 
W 

o 

O 
P. 



00 

6 

c 






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1 82 The Gas Engine 

These results are obtained using Manchester gas. 
Mr. G. H. Garrett has made a trial with an 8 HP Otto engine 
in Glasgow, the diagram and particulars of which are given on 

fig. 55- 

Summary of Experiments, — From these numerous and careful 
experiments, conducted quite independently of each other by 
many observers, it may be taken as abundantly established that 
the Otto engine is a great advance in economy and certainty of 
action upon any gas engine preceding it. On the Continent and 
in America the consumption per horse power hour is, on the 
whole, greater than in Britain ; this is due not to any appreciable 
difference in the efficiency of the engines made here, but to the 
better gas common in this country. 

Calculations of the efficiency attained in some of the later engines 
in England, show that as much as 18 per cent, of the heat is con- 
verted into work as shown by the indicator. Dr. Slaby's value is 
16 per cent., and Professor Thurston's 17 per cent. All observers 
agree that the heat liberated at the moment of completed explosion, 
that is, of highest temperature, is roughly one-half of the total heat 
present as coal gas, the remaining half being evolved during the 
expansion period. Professor Thurston gives the heat of the ex- 
plosion as 60 per cent of the total heat present, Dr. Slaby as 55 
per cent The author's experiments upon the heat evolved by 
the explosion of different mixtures of gas and air, show heat 
accounted for by the explosion as ranging from 50 to 60 per cent, 
agreeing with the determinations of Bunsen, Hirn, Mallard and 
Le Chatelier, and Berthelot and Vieille. It may therefore be 
considered as absolutely proved that this suppression of heat at 
explosion, and its evolution during expansion, is a phenomenon 
inherent in every explosive mixture, however made — a thing, in 
fact, from which there is no escape. In whatever way an engine 
be made, if it explodes or burns a mixture of any inflammable 
gas with any mixture of gases containing oxygen, then this slow 
combustion or, as the Germans have it, nachbrennen (after-burn- 
ing) is unavoidably occasioned. Knowing this, and knowing of 
Him, Bunsen, and Mallard and Le Chatelier's work long prece- 
dent to Dr. Slaby's report, it is surprising to find so able and 
learned a scientist quoted as stating that in the Lenoir engine 



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Gas Engines of Different Types in Practice 183 

the whole heat was evolved at the moment of complete explosion. 
In the Lenoir, as in, every other gas engine which has ever 
been constructed, not more than one-half of the whole heat of 
the gas present is then evolved, the remaining heat being evolved 
on the expanding stroke. 

Schottler falls into the same error, and, although mentioning 
Wedding's statement of Bunsen's law of dissociation, shows that 
he rejects it when he assumes that the whole heat is evolved. A 
very cursory examination of the Lenoir diagram would at once 
prove to Prof. Schottler that Lenoir did not succeed in so 
escaping the laws of nature ; had he done so, there would have 
been no necessity for our modern improvements. 

The consumption of continental gas may be taken as varying 
between 32 cb. ft. and 35 cb. ft. per effective HP per hour, and 
about 28 cb. ft per I HP per hour. 

In Britain it may be taken as ranging from 24 cb. ft pel 
effective HP to 33 cb. ft., and 20 to 24 cb. ft. per IHP per hour, 
depending upon the quality of gas used and on the dimensions 
of the engine tested. Other things being equal, better results 
are obtained with large engines. The theoretic efficiency is con- 
stant for both large and small engines where the same compression 
is in use, but the loss of heat from the explosion to the sides of 
the cylinder is less in the large engines, due to the diminished 
surface exposed in proportion to the volume used. The effect is 
to increase the efficiency of the gas in the mixture used, a 
smaller quantity being necessary to make up for the loss of 
heat. 

The indicator diagrams prove the very efficient nature of the 
Otto cycle. The great simplicity attained by the alternate use of 
the cylinder as pump and motor diminishes the number of valves 
necessary, and secures the minimum resistance to the entering 
gases, while entirely preventing any loss due to ports, in trans- 
ferring the gases from one cylinder to another. The carrying out 
of the cycle is mechanically almost perfect, no work being spent 
which is not included in the theory. Again, the piston is full in 
at the moment of ignition and is almost at rest ; the heat, pro- 
ducing maximum temperature, is therefore added at nearly 
constant volume. The highest pressure which the gas present is 



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184 The Gas Engine 

capable of producing is therefore attained at the beginning of the 
stroke simultaneously with the highest temperature ; the succeed- 
ing expansion is then very rapid, and so no unnecessary waste of 
heat occurs, the temperature being rapidly depressed by work 
being done. The united effect of all the arrangements is seen in 
a diagram which is almost theoretically perfect ; the only de- 
duction from theory is due to the unfortunate property of explo- 
sive mixtures of continued combustion after explosion. And 
this reduces the theoretic efficiency to one-half in practice. The 
theoretic efficiency of all Otto engines, of whatever dimension, is 
0-33, as the compression space in all cases bears nearly the ratio 
of 06 to 1 -o when compared with the cylinder volume which is 
swept by the piston. The actual indicated efficiency is very 
nearly one-half of that number. 

If combustion by any means could be made complete at the 
highest temperature and pressure at the beginning of the stroke, 
instead of continuing as it does well into the expansion stroke, 
then greatly increased economy would result, and in large engines 
theory might be very nearly approached. 

This point will receive further discussion later on. 

Clerk Engine, — Otto's method is probably the readiest and 
easiest solution of the problem of attaining in a practicable 
manner the advantages of compression ; in some points, however, 
the advantages are accompanied with compensating disadvantages. 

Only one impulse for every two revolutions is obtained ; the 
engine is therefore stronger and heavier than need be if impulse 
every revolution were possible. It is also more irregular in its 
action than more frequent impulses would give. 

The Clerk engine was invented by the author with the view of 
obtaining impulse at every revolution, while getting at the same 
time the economy due to compression. 

At first blush it seems a very simple matter to make a com- 
pression gas engine to give an impulse for every revolution ; this 
was the author's opinion when he commenced work for the first 
time upon gas engines using compression in October 1876. Since 
then he has had occasion to modify the opinion : the difficulties 
are very great ; any engineer who doubts this will speedily be 
convinced upon making the attempt. 



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Gas Engines of Different Types in Practice 185 

It was not till the end of 1880 that the author succeeded in 
producing the present Clerk engine ; before that time he had 
several experimental engines under trial, one of which was ex- 
hibited at the Royal Agricultural Society's show at Kilburn in 
July J 879. This engine was identical with the Lenoir in 
idea, but with separate compression and a novel system of 
ignition. 

The Clerk engine at present in the market was the first to 
succeed in introducing compression of this type, combined with 




Fig. 56.— The Clerk Gas Engine. 

ignition at every revolution ; many attempts had previously been 
made by other inventors, including Mr. Otto and the Messrs. 
Crossley, but all had failed in producing a marketable engine. 
It is only recently that the Messrs. Crossley have made the Otto 
engine in its twin form and so succeeded in getting impulse at 
every turn. 

In the Clerk engine the whole cycle is completed in one re- 
volution, and an impulse given to the crank on every forward 
stroke of the piston, when working at full power. 

The engine contains two cylinders, one for producing power, 



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1 86 The Gas Engine 

the other for taking in the combustible charge and transferring it 
to the power cylinder. At the end of the motor cylinder is left 
a compression space of a conical shape, and communicating with 
the charging or displacing cylinder by a large automatic lift-valve 
opening into the space ; at the other end of the cylinder are placed 
V-shaped ports opening to the atmosphere by the exhaust pipe ; 
the motor piston, when near its outer limit, overruns these ports 
and allows the cylinder to discharge. The pistons are connected 
in the usual manner by connecting rods, the motor to the main crank 
of the engine, the displacer to a crank pin in one of the arms of 
the fly-wheel; the displacer crank is in advance of the motor crank, 
in the direction of motion of the engine, by a right angle. The 
displacer piston on its forward movement takes in its charge of 
gas and air, and has returned a fraction of its stroke when the 
motor piston uncovers the exhaust ports. While crossing the centre, 
opening and shutting these ports the displacer piston has moved 
in almost to the end of its cylinder, discharging its contents 
into the space and forcing out at the exhaust ports the products of 
the previous ignition. The proportions of the two cylinders are so 
arranged that the exhaust is as completely as possible expelled, 
and replaced by cool explosive mixture, which thoroughly mixes 
with any exhaust remaining, cooling it also to a considerable 
extent. Care must be taken in the arrangement of the parts 
that an excessive volume is not sent from the displacer, 
otherwise it may reach the exhaust ports and gas discharge 
unburned. 

The return stroke of the motor piston now compresses the 
mixed gases, and when at the extreme end, the igniting valve fires 
the mixture, the piston moves forward under the pressure thereby 
produced, till the opening of the exhaust ports causes discharge 
and replacement as before. In this way an impulse is given at 
every revolution, and the motive power applied to greater advantage. 
The motor cylinder is surrounded by water for cooling, but this 
is unnecessary with the displacer, as it uses only cool gases. The 
pressures used are high, so that both motor piston and its connec- 
tions are made very strong ; the pressure on the displacer piston 
is very little, so the connections are light. It is not a compressing 
pump, and is not intended to compress before introduction into 



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Gas Engines of Different Types in Practice 187 

the motor, but merely to exercise force enough to pass the gases 
through the lift valve into the motor cylinder, and there displace 
the burnt gases, discharging them into the exhaust pipe. The 
pressure to be overcome is only that due to resistance in the 
exhaust pipes and the lift valve. 

The inlet valve for gas and air is also automatic ; its seat is of 
the usual conical kind but somewhat broad. A gutter runs round 
the centre, having small holes bored through to a recess behind, 




Fig. 57.— Longitudinal Section of Clerk Gas Engine. 

which communicates with the gas supply pipe. The suction lifts the 
valve to a certain height, and, as the gases enter, the air flows past 
the holes and becomes thoroughly impregnated with gas, the 
extent being determined by the number of holes and the propor- 
tion of their area to the total area of the valve opening. The 
upper valve is made heavy to withstand the maximum pressure of 
the explosion ; both valves are arranged so that the guide forms 



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1 88 The Gas Engine 

a piston working in an air cylinder, so arranged as to check 
the fall of the valve before touching the seat, and so prevent any 
disagreeable rattle. 

Description of the Drawings. — Fig. 56 is a general view of the 
engine. Fig. 57 a longitudinal section. Fig. 58 a sectional plan. 
In these drawings all the essential parts of the engine are repre- 
sented ; the sectional plan (fig. 58) shows the two cylinders, 
motor a and displacer b, in which work the pistons c and d 
suitably connected to cranks not shown in the drawing, but on a 
common crank shaft. The motor crank is double and of great 
strength ; the displacer crank pin is fixed into an arm in the fly- 
wheel, and in the direction of motion of the engine is a half right 
angle or quarter circle in advance. The motor piston is shown at 
its extreme out-stroke, having passed over the exhaust ports e e 1 , 
the piston thus serving as its own exhaust valve, and dispensing 
with any other, as shown ; the displacer piston has moved half in 
and discharged a portion of the contents through the valve f 
(more distinctly seen in the other section, fig. 57) into the conical 
space g, which is so proportioned that the entering gases push 
before them the burned gases through the ports referred to, but 
without following them into these ports. By the continued move- 
ment, all the gases in b pass into a and the space g; the capacities 
of the two cylinders are so related that as much as possible of the 
burnt gases is discharged into the atmosphere, but without carrying 
away any of the fresh mixture containing unburned gas; this neces- 
sitates the mixture next the piston being somewhat more dilute 
than that next the inlet valve, but the commotion occasioned by 
compression so far equalises this undesirable state of things that at 
half in-stroke the mixture in its weakened portions is quite capable 
of inflammation by a light or the electric spark. The piston d 
having completed its in-stroke, c has passed over the discharge 
ports and compresses the contents of the cylinder into the space g; 
when full in and therefore completely compressed, the slide valve 
m has moved into such a position as to ignite the mixture ; the 
maximum pressure being attained very rapidly and before the 
piston can move appreciably on its out- stroke, the piston is impelled 
forward under the pressure produced until it reaches the ports e e 1 , 
when the contents are rapidly discharged, and the interior and 



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Gas Engines of Different Types in Practice 189 







c 



8 



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ipo 



The Gas Engine 



exterior pressures equalised. Meantime the piston d being in 
advance of the motor has moved to the end of its stroke and is 
beginning to return, it has charged the cylinder b with a mixture 
of gas and air from the automatic valve h (fig. 57), the commu- 
nication being made by the pipe w (fig. 58). In the seat of this 
valve are bored a number of small holes passing into the annular 
space k k 1 (f\g. 57), which communicates with the gas cock l (fig. 
58) through the passage shown, in which is situated the lift-govern- 
ing valve, not seen. Under the deficit of pressure caused by the 

Upper lift valve. 



— Quieting piston. 

_ - Lower lift valve. 
Gas channel. 

••Quieting piston. 



Fig. 59.— Section of Lift Valves. Clerk Engine. 



movement of the displacing or charging piston, the valve is lifted 
and the exterior atmosphere rushes through, at the same time the 
gas passing through the holes mixes with it thoroughly, the pro- 
portion being determined by the relative areas of the holes and 
the space available for air by the lift of the valve. 

The gases in b are under some slight compression before the 
complete discharge of a, but not sufficiently great to cause any 
material resistance ; so soon as the pressure under the valve f is 
slightly in excess of that above it, then it lifts and the gases pass 
into o. The passage from the valve, which may be called the 




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Gas Engines of Different Types in Practice 191 

upper lift valve, is more clearly seen in fig. 57 : the igniting hole 
is shown at n, and communicates at the proper time with flame in 
the cavity o, which has been ignited at the exterior flame p, from 
a Bunsen burner (fig. 58). 

The two automatic valves charging the displacer cylinder and 
discharging into the motor cylinder are provided with quieting 
pistons, cushioning the blow on the valve seat and preventing 
rattle; they are similar to the dash pot contrivances used on 
Corliss' steam engines to check the snap of the steam valves, but, 
unlike them, are attached directly to the valve, instead of to the 
*valve spindle and guide. The arrangement is very clearly seen at 
fig- 59 : tne lower valve has no spring, it returns to its seat by its 
own weight ; but the upper valve requires to act more quickly 
and is pulled down by a spring. 

The piston attached compresses the air before it, and the 
valve strikes its seat rapidly but without jar or recoil. 

The igniting slide, m, is driven from an eccentric on the crank 
shaft through a bell crank and guide. 

Diagrams and Gas Consumption. — The following tests give 
the latest results from the Clerk engine ; they are the usual trials 

Tests of the Clerk Engines of various Powers. 



Diameter of motor cylinder 

Stroke 

Diameter of displacer cylinder . 
Stroke . 

Average revs, permin. during test 
Average pressure (available) in 

motor cylinder in lbs. per sq. in. 
Power indicated in motor cylinder 
Power by dynamometer \ 
Gas consumption in cb. ft per 

IHP per hour 
Gas consumption per brake HP 

hour 

Max. pressure of explosion in lbs. 

per sq. in. above atmos. 
Pressure of compression in lbs. 

per sq. in. above atmos. 
Displacer resistance . . . 
Gas consumed per hour by each 

engine at spee 1 without load . 



2 HP 


4 HP 

6 ins. 
10 ins. 


6 HP 

7 ins. 
' 12 ins. 


8 HP 


12 HP 


5 ms « 
8 ins. 


8 ins. 
16 ins. 


9 ins. 
20 ins. 


6 ins. 


7 ins. 


7i ins. 


10 ins. 


10 ins. 


9 ins. 

212 


11 ins. 
190 


12 ins. 
1 146 


13 ins. 
142 


20 ins. 
132 


43 '2 
362 
270 


63 9 
8*68 

5' 6 3 


' 53 '2 
9 'OS 
723 


60-3 
17 38 
1309 


64-8 ' 
2746 j 
23-21 , 


298 


24*19 


24 "3 


20-94 


20-39 


40 'O 


37 "3 


30-42 


2658 


1 
24*12 


155 lbs. 


236 


195 


195 


238 


38 lbs. 
040 


55 
080 


1 48 
• o-86 


49 
*'5<> 


57 
2 00 


40 cb. ft. 


58 cb. ft. 


57 cb. ft 


70 cb. ft 


90 cb. ft 



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192 



The Gas Engine 



made by Messrs. L. Sterne and Co. on all engines before leaving 
the works, and therefore represent fairly the economy to be 
expected from these engines in ordinary work. They are from 
2, 4, 6, 8, and 12 HP engines (nominal). The trials were made 
during 1885 at the Crown Iron Works, Glasgow, under the 
direction of Mr. G. H. Garrett. 

Figs. 60, 61, 62 are fair samples of the diagrams taken during 
the tests. Figs. 63 and 64 are diagrams from the displacers 
showing the dispiacer resistance. 




Nominal HP, 6 ; diam. of cylinder, 7" : length of stroke. 12' 
dicated HP, 9 05 ; consumpt. per I HP, 2430 cb. ft. 



No. of revs. 146 : in- 

. r „ . «--- «- , — , .,- --. ... . consumpt. loose, 57 cb. ft. : 

brake HP, 7-25 ; consumpt. per BHP, 30*42 cb. ft. ; mean pressure, 532 lbs. : max. 
pressure, 195 lbs. ; press, before ignition, 48 lbs. : scale of spring, i a, 7 " per lb. 



Fig. 60.— Diagram from Clerk Gas Engine, 6 HP. 

Calculating from these diagrams the actual indicated efficiency 
it comes to 16 per cent of the total heat given to the engine. 

The compression space in the Clerk engines is as nearly as 
possible one-half of the volume swept by the piston from the 
exhaust port to the end of its stroke. The theoretic efficiency is 
therefore 

— -©•—-©*•-•* 

The compression is higher, and therefore the theoretic efficiency- 



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Gas Engines of Different Types in Practice 193 

of this engine is higher than the Otto, but the difficulties of pro- 
portioning the two cylinders of the Clerk engine cause a small 
loss of unburned gas at the exhaust ports, so that the actual 
efficiency is similar to that of Otto. 

The mixture sent from the displacer cylinder into the motor 
and the space at the end of it, contains 8 vols, of air with 
1 voL of coal gas, but on passing through the upper lift valve 
and mixing to some extent with the exhaust there contained, it 
is somewhat diluted; the heat acquired by contact with the 
products of combustion and with the sides of the cylinder expands 
the entering gases, and a temperature of not less than ioo° C. is 



^~^ » * "° 

1 1 — ■*■ *** 

/dr * » j — --^ 



Nominal HP, 8 ; diam. of cylinder, 8" ; length of stroke, 16" ; No. of revs. 14a : 
indicated HP, 17*38; consumpt. per I HP, 2094 cb. ft. ; consumpt. running light 
per hour, 70 cb. ft. ; brake HP, 13*69 ; consumpt. per B HP, 26*58 cb. ft. ; mean 
pressure, 60*3 lbs. ; max. pressure, 195 lbs,; pressure before ignition, 49 lbs. ; scale 
of spring, Tr ," per lb. 

Fig. 61.— Diagram from Clerk Gas Engine, 8 HP. 

attained before the compression commences. The result of this 
is, that the displacer gases, being expanded, expel more of the 
exhaust gases through the discharge ports than would appear 
from the volume swept by the displacer piston. This volume is 
equal to the volume swept by the motor piston, from closing of 
the exhaust ports to complete in-stroke. If no expansion and no 
mixing occurred, the exhaust gases contained in the compression 
space would remain in front of the cooler explosive charge; but 
the heat increases the volume at least one-third, so that the 



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194 



The Gas Engine 



volume occupied will be i^ times the volume swept by either 
piston. The volume of cylinder plus space is i^ vol. of cylinder, 





ual exhaust gases present are £ vol., or -j^ of the 
nt But mixing must occur to a considerable 
* made very complete on the return stroke during 



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Gas Engines of Different Types in Practice 195 

compression. The result of all this is the production of an explosive 
mixture which is explosive in every part of it, and of an average 
composition of one volume of coal gas in ten of the mixture. 
The proportion of burned gases present is very slight ; the only 
reason why any should be left is the necessity of preventing any 



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appreciable discharge of unburned gas at the exhaust ports. The 
mixture used is a comparatively rich one. 

Tangye Engine, — Messrs. Tangye, of Birmingham, have pro- 
duced an engine in which compression of the kind common to the 
third type is used and an ignition is obtained for every revolution 

02 



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196 The Gas Engine 

when at full power. It is Robson's patent and contains only one 
cylinder. All the necessary operations of charging, compressing, 
and igniting are fulfilled with one cylinder ; it is arranged as in an 
ordinary steam engine. The front end of the cylinder unlike the 
Otto and Clerk engines is closed, a piston rod, cylinder cover, 
and stuffing box being provided, as in steam. The front end of 
the cylinder serves for charging, the back end for compression 
and explosion. 

There is a compression space at the back end of the cylinder as 
in the other engines. 

The action is as follows. During the return stroke, gas and 
air mixture is drawn into the front end of the cylinder at atmo- 




Fig. 65.— Robson's Gas Engine. 

spheric pressure, through an automatic valve. The next out-stroke 
compresses the mixture into a large intermediate chamber at a 
pressure of not more than ^syt, lbs. per sq. in. above atmosphere. 
When full out and the exhaust ports therefore open, this pressure 
lifts a valve leading into the compression space of the engine, dis- 
charging before it the gases contained in the cylinder through the 
exhaust valve and filling the cylinder and space with explosive 
mixture. This reduces the pressure in the intermediate reservoir 
to atmosphere so that the next in-movement of the piston com- 
presses the explosive mixture upon one side of the piston and takes 
in fresh mixture on the other side. 



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Gas Engines of Different Types in Practice 197 

When compression is completed the igniting valve acts and the 
explosion impels the piston ; so soon as the exhaust ports open, the 
pressure falls to atmosphere, and then the reservoir pressure being 
superior to that in the cylinder, the automatic valve acts and the 
fresh charge enters. 

Thus an explosion is obtained at every revolution by using the 
front end of the cylinder as displacer and storing up the pressure 
in an intermediate reservoir. 

The governing is managed by cutting off gas supply, but is 
hampered considerably by the intermediate chamber. Fig. 65 
is an external view of the engine, which is exceedingly neat and 
of substantial workmanship. 

The Stockport Engine, — This engine is similar to Robson's 




Fig. 66. — The Stockport Gas Engine. 

in theory but the front end of the cylinder is not used for charg- 
ing, the piston being made a double trunk with the crank be- 
tween, and one end and one cylinder being motor, the other end 
and the other cylinder being displacer. Compression occurs in 
the motor cylinder. Fig. 66 shows the external appearance. The 
valve arrangements differ from those of Messrs. Tangye. It is 
made by Messrs. Andrew, of Stockport. 

Atkinsoris Differential Engine. — The description of engines of 
this type would be incomplete without mention of this engine, 
exhibited at the Inventions Exhibition for the first time in 1885. 
It Is exceedingly ingenious and quite novel 



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198 



TIte Gas Engine 



Fig. 67 is an elevation, fig. 68 a section, and fig. 69 a plan. 
The action is very clearly seen from the different positions on fig. 
70. 

The same cylinder serves for all purposes of the cycle ; two 
trunk pistons, working in opposite ends of it are connected to 



LEVATION 




Fig. 67. — Atkinson's Differential Gas Engine. 

the levers and from thence to the crank shaft by the connecting 
rods. The short rods cause the necessary actions. 

In the first position, fig. 70, the pistons are at one extreme of 
their stroke, and are just beginning to separate. The charge of gas 



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Gas Engines of Different Types in Practice 199 

and air enters between them through the automatic lift valve, and 
in position 2, the charge has entered and the further movement 
of the piston is about to close the port leading to the admission 
and exhaust valves. The compression thus commences and in 
position 3 it is completed. The ignition occurs and the pistons 



SECTION 




Fig. 68. —Atkinson's Differential Gas Engine. 

now rapidly separate, the exhaust port being uncovered and the 
discharge commencing in position 4. By this clever method 
the whole operations of admission, discharge, ignition, and expan- 
sion are performed in the single cylinder with only two automatic 



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200 



The Gas Engine 



PLAN 




Fig. 69. — Atkinson's Differential Gas Engine. 





'' N 4 




Fig. 70. — Atkinson's Differential Gas Engine. 



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Gas Engines of Different Types in Practice 201 

valves which are never exposed to the pressure of explosion, the 
pistons acting in some part as valves and uncovering the exhaust 
and inlet ports when required. In the other extreme position they 
also act as valves, the outside piston uncovering the igniting port 
at the correct time. Sufficient experience has not yet been accu- 
mulated with this engine to speak positively as to its performance. 
To the author, the principal disadvantage appears to lie in a com- 
pression space of diameter so great, in proportion to depth, that the 
ratio of cooling surface to volume of hot gases is largely in excess 
of that common to other engines. This disadvantage will diminish 
ihe economy which the great expansion would otherwise give. 



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202 The Gas Engine 



CHAPTER VIII. 

IGNITING ARRANGEMENTS. 

However perfect the theoretic cycle of an engine, or however 
admirable is its construction, in the absence of a good igniting 
valve the skill and energy expended is of no avail. The engine 
is a useless mass of metal requiring power to move itself rather 
than furnishing power to set other machines in motion. 

In the earlier stages of gas engine manufacture, the igniting 
method has been the most fruitful source of annoyance and diffi- 
culty ; even yet, after many years of engineering experience, the 
igniting valve is still the initial difficulty which the inventor must 
overcome before he gets the opportunity of testing his theories of 
heat and work in a moving machine. Quite a number of wit- 
nesses, in the shape of unworkable gas engines, in many engineers' 
workshops throughout Britain, attest silently but emphatically the 
difficulties of the igniting valve. 

The problem is by no means a simple one, and the care 
lavished upon its solution would not be suspected on inspection 
of the igniting gear of any good modern engine. Much has been 
done, but much still remains yet to be accomplished before flame 
is as completely and effectively under control as steam. 

In the noncompression engines the problem is comparatively 
simple — to inflame a volume of explosive mixture enclosed in 
a cylinder, so that the explosion is confined within the cylinder, 
and no communication is open to atmosphere. This is to be re- 
peated regularly and with certainty at rates varying from 60 to 150 
times per minute, depending upon the speed of the engine. In 
the earlier trials, what may be called the touch hole method 
naturally suggested itself; the piston after taking in its charge, 
crossed a small hole and sucked a flame through it into the cylin- 



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Igniting A rrangenunts 203 

der, the hole being either small enough to occasion no substantial 
loss of pressure upon explosion, or covered by a small valve closing 
with the pressure from the interior. This is the earliest flame 
method Then comes the idea of using the electric spark, and so 
completely closing up the cylinder, and, later on, a return to flame, 
using a double flame, one to ignite an intermediate one, and 
the intermediate flame carried in a pocket or hollow cock to the 
mixture. Then the idea of spongy platinum suggested by the 
well-known Doebereiner's Hydrogen lamp. Later on the heating 
of metal tubes or metal masses and the ignition of the gases by 
contact with them. Then electrical ignition again, but this time 
by heating a platinum wire to incandescence. All those methods 
were proposed and to some extent practised long before gas 
engines appeared in any commercially successful form. 
Ignition methods may be classed in four distinct groups. 

(1) Electrical methods. 

(2) Flame methods. 

(3) Incandescence methods. 

(4) Methods depending on ' Catalytic ' or chemical action. 

(1) Electrical Methods. 

Spark Method. — The use of the electric form of energy seems 
at first sight a very convenient and easy method of getting an in- 
tense heat at any desired time and in any desired spot in the 
interior of a cylinder. The electric spark has long been used by 
chemists to explode the contents of the eudiometer in which gas 
analysis is effected ; and the platinum wire rendered incandescent 
by the current from a battery has long been familiar to experi- 
menters and is used by them for many purposes. The spark 
method was used in the Lenoir engine. A Bunsen's battery, a 
Rumkorff induction coil, and a commutator or distributor, is 
required in addition to the insulated points between which the 
spark passes in the interior of the cylinder. 

Fig. 71 is drawn to show clearly the general arrangement. 
The Bunsen's battery a generates the current, which passes by the 
wires to the coil b, from which the intensity current passes to the 
insulated points d d by way of the distributor c. The negative 
pole of the coil is permanently connected to any part of the metal 



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204 



The Gas Engine 



work of the engine ; the igniting points d, d, consist of porcelain 
plugs seen on a larger scale at e. The porcelain is firmly 
cemented into the brass nut i, and the wire 2 which passes through 
a hole in the plug terminates outside in the connecting screw 3, 
and inside is bent over the end of the plug ; the other wire 4, 
. passes through another hole in the plug, is bent over in the inside 
lying near the wire 2 but not touching it, it then passes through 
the side of the plug touching the metal of the nut. When the 
nut is screwed into position the one wire is in metallic conneo 
tion with the cylinder of the engine, and the other is insulated 
from it. 







Fig. 71. — Ignition Arrangements Lenoir Engine. 

The distributor c consists of an insulated metallic arm 1 rota- 
ting on the end of the crank shaft over the insulated ring 2, which 
is connected to the positive pole of the coil. Two insulated seg- 
ments 3, 4, are connected by wires to the igniting plugs d, d ; in 
rotating, the arm 1 comes alternately over 3, 4, and it is within 
sparking distance of the ring 2 as well as the segments ; the sparks 
pass alternately to the segments and thence alternately to the 
opposite ends of the cylinder. The ebonite disc carrying the seg- 
ments and ring is so adjusted that the spark begins to pass at either 
end, just as the admission valve closes. If it passed too soon the 



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Igniting A rrangements 205 

explosion would occur before the admission valve closed, and 
therefore would partly be lost, and at the same time would make a 
disagreeable noise. If it is passed too late, power is lost, because 
the piston is at its most rapid rate of movement and is reducing 
the pressure of the cylinder contents uselessly. 

Notwithstanding the most careful adjustment, some time 
elapses between the closing of the admission valve and the explo- 
sion. When all is in good order this arrangement works very well, 
but should the insulation be disturbed and any short circuiting 
occur, the spark fails to pass between the points in the interior of 
the cylinder and a missed or late ignition results. This often 
happens in starting the engine when it is cold ; the first few explo- 
sions cause a condensation of water upon the points and the spark 
then fails, the current passing through the water film from wire to 
wire without spark. The igniters then require to be uncoupled 
and dried. To reduce this trouble, the poinds are kept towards 
the top of the cylinder in the end covers so that any water or oil 
drainage may flow down and leave them dry. The difficulties of 
insulation, coil and battery, are so great that they did much to 
prevent the use of the Lenoir engine ; unless the machine fell into 
intelligent hands it was sure to go wrong and give trouble. 

The spark method has never been applied to compression 
engines as the compression increases all difficulties. The Lenoir 
igniting plug, or ' inflamer ' as it was called, if put in a compression 
engine leaks badly and cannot be got to act efficiently. Many 
specifications of compression and other engines state that ignition 
is accomplished by the electrical spark, but the Lenoir engine alone 
attained any success. 

Incandescent Wire Method, — This method very naturally suggests 
itself as a solution of the difficulties of the high tension spark; the 
coil is dispensed with and the current from the battery is applied 
directly to heat a thin platinum wire. The difficulty of insulating is 
very slight. The tension being low it is a matter of indifference 
whether the insulating material is wetted or not The wire being 
constantly at a red heat cannot remain at all times in the cylinder, 
but is put into communication with it at proper times by means of 
a slide valve. Fig. 72 is a drawing of an igniting slide of this kind, 
as used by the author in experimental work. It acts very well in- 



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206 



T/ie Gas Engine 



deed. The screw i carries the insulated rod 2, insulated by means 
of asbestos card-board packed into the space and screwed down 
firmly by the screw 3. The other wire is screwed into the metal 
and so is in metallic connection with the metal work of the 
engine. One wire from the battery connects to any portion of the 
engine ; the other is insulated. The platinum wire 4 is thus kept 
continually at a red heat, and the slide 5 moving at proper times 
causes the gases to be ignited to flow into the chamber containing 
the platinum spiral, by the hole 6, and so causes the explosion. 




Fig. 72.— Electrical Igniting Valve (Clerk). 
Incandescent Platinum Wire. 

There is only one precaution required in using this. The battery 
must not be too powerful ; if the wire is heated by it to near its 
fusing point, then the further heat supplied by successive explo- 
sions may cause its destruction. It requires to be kept at a good 
red heat and no more when open to the air : when closed up and 
in contact with the hot gases it will then become almost white hot ; 
anything above this may fuse it. The battery is of course at all 
times a source of care ; as it requires to be often renewed, it is only 
for experimental work that this arrangement answers well In the 
hands of the general public it would come to grief. Hugon and 



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Igniting Arrangements 207 

many others proposed similar arrangements, but they do not appear 
to have worked them out 

Arc Method, — There is another electrical method A small 
dynamo attached to the engine keeps up a continuous current and 
heavy platinum points in communication with the cylinder carry 
the arc. This is difficult, however, as the points constantly volatilize 
and require frequent renewal. This method has never come into 
practical use ; it is described several times in specifications. 

(2) Flame Methods. 

The earliest really efficient igniting valve is that described by 
Barnett in his specification of 1838. It is the parent form of 
the most extensively used valve, the 'Otto.' 

Barnetf s Igniting Valve. — Fig. 73 shows a vertical section and a 
plan of this valve. It consists of a conical stopcock with a hollow 
plug; the shell contains two ports, 1 and 2— 1 open to the atmosphere 
and 2 communicating with the cylinder. The plug of the cock has 
one port, 3, so arranged that it may open on the atmosphere port or 
the cylinder port in the shell, but cover enough being left to pre- 
vent it opening to both at the same time. In turning round it 
closes on the atmosphere before opening to the cylinder. 

A gas jet burns at the bottom of the shell, and in the hollow 
of the plug, the ports 3 and 1 being long enough and wide enough 
to allow the air free circulation as shown by the arrows. The flame 
must not be too large or it will fill the whole interior with gas and 
prevent air getting in; the flame will then burn at the port 1 in the 
air and will not enter the cock. Suppose it to be burning regu- 
larly in the cock as shown in the drawing, then if the plug is suddenly 
turned round so that port 3 closes upon the atmosphere port 1, 
and opens upon the cylinder port 2, the air supply will be sufficient 
to keep the flame living till the mixture contained in 2 reaches it 
The explosion then occurs. The port 2 is of the same shape as i, 
so that the flame causes the gases to circulate the same as the air 
did when open to it ; the mixture comes in contact with the flame 
by circulating through the plug. If the port 2 is made so small 
that no circulation occurs, then the ignition will be a very uncer- 
tain matter ; as the gases will require to get at the flame by diffu- 



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208 



T/ie Gas Engine 



sion, which is a slow process, and the flame may be extinguished 
before they arrive at it. The explosion of course extinguishes the 
flame, but when the plug is again rotated to open to the air, the 
external flame relights it and it is ready for another ignition. 





Fig. 73.— Bamett's Igniting Valve (flame). 



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Igniting Arrangements 209 

ffugon's Igniting Valve. — In the small Hugon engine Barnett's 
method was first applied in a fairly successful manner. 

The valve is shown in section at fig. 74. 

The sectional plan, fig. 74, shows the internal flame lit and 
burning in the ignition port 1 ; the external flame 2 burns close to 
it in this position, so as to be ready to light it when wanted The 
gas for the internal flame is supplied under higher pressure than 
that of the ordinary gas mains by a bellows pump and small 
reservoir through the flexible rubber pipe. For the external flame 
the gas is used at the ordinary pressure. 

When ignition is required, the valve moves rapidly forward 
causing the port 1 to close to atmosphere first, and then to open 
to the cylinder port 3, as shown at the other end of the slide. 

The explosive mixture which fills the port 3 is at once 
ignited and the flame finds its way from the port into the cylinder 
itself ; the port is necessarily filled with pure explosive mixture 
free from any admixture with exhaust gases, as all the mixture 
before entering the cylinder must pass through it and so sweep 
before it any burned gases into the cylinder. Hence the mixture 
in the port will be more ignitable than that in the cylinder, as the 
mixture there is diluted in part with exhaust gases while that in 
the port is free from them. 

The explosion is thus exceedingly certain and regular ; when 
it occurs it extinguishes the internal flame and at the same time its 
superior pressure forces back the gas in the rubber pipe while the 
port 1 remains open to the cylinder. 

The return of the slide again opens it to the atmosphere, and here 
is seen the necessity of using the gas under some pressure. Before it 
can relight at the external flame, the products of combustion must be 
expelled from the gas pipe ; if the gas were under only the ordinary 
gas main pressure there would be no time for this, and the valve 
would return to ignite without a flame. The expedient of increas- 
ing pressure is somewhat clumsy but it acts fairly well. The port 1 
is made large to give space for the air necessary to support the 
flame while the ignition port is passing from atmosphere to 
cylinder port At the moment of explosion, the cylinder is com- 
pletely closed from the air. 

p 



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2IO 



Tlie Gas Engine 



The explosion is therefore completely contained within the 
cylinder and no sound is heard. 



— ■ — -i i 




I 



h 

6 



I 

6 



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Igniting A rrangetnents 2 1 1 

In the engine at the Patent Office Museum Mr. S. Ford con- 
siderably improved the igniting arrangement by intercepting the 
rush back to the gas pipe by a light check valve ; he was thus able 
to use gas under the ordinary gas main's pressure and dispense 
entirely with Hugon's gas pump and reservoir. The explosion, in- 
stead of forcing a considerable volume of burned gases down the 
gas pipe, simply closed the check valve, which opened as soon as 
the igniting port reached the air again, and so gave the gas stream 
at once. 

Otto's Igniting Valve. — The igniting valve used in the Otto 
and Langen engines is a further development of Barnett and 
Hugon's igniting devices. 

As applied to the compression engine there is one alteration, 
very slight, but very essential. 

In the Lenoir and Hugon engines, as well as the Otto and 
Langen, the pressure in the cylinder is the same, or in some cases 
less than that of the external atmosphere, that is, before ignition. 
It is therefore an easier matter to transfer a flame burning quietly 
in the air to the cylinder without danger of extinction. When the 
gases to which the flame is to be transferred exist at a pressure 
some 40 to 50 lbs. per square inch superior to that of the flame 
itself, it is not so easily seen how the flame is to be transferred 
without extinction. Generally described the arrangement is as 
follows. A small quantity of coal gas is introduced into the 
upper part of a cavity in the ignition slide ; being lighter than air it 
remains separate from it and has no tendency to mix with the air 
beneath it, except by the slow process of gaseous diffusion. At the 
surface of contact with the air, it is ignited and burns with a blue 
flickering flame. The movement of the slide cuts off communica- 
tion with the outer atmosphere, and very shortly thereafter opens 
on the admission port of the engine, but before doing this it opens 
on a small hole communicating with the cylinder. This hole com- 
municates with the gas passage in the upper part of the slide, so 
that the gases under pressure enter and force the gas downwards, 
the pressure rising in the port more slowly than would occur if 
the main port opened at once. The pressure is therefore nearly 
level with that in the cylinder when the main port opens, and the 
flame still burning at the point or surface of junction between the 

v 2 



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212 



T/ie Gas Engine 



gas and air, ignites the mixture. If the pressure was not raised 
in the igniting port by pressing the gas downwards and thereby 
avoiding a rush past the flame portion, the rush would often 
extinguish the flame and an ignition would be missed. The 
apparent difficulty of transferring the flame from atmosphere to 




Fig. 75.— Section, Otto Igniting Valve. 

40 lbs. above it is thus simply and beautifully overcome By using 
a portion of gas in the upper part of the valve cavity, the difficulty 
of the blow back of explosion down the gas supply pipe is also 
overcome, as the gas supply can be cut off before the explosion or 



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Igniting A rrangements 213 

compression pressure comes on. It is cut off just before the valve 
closes the flame port to atmosphere. 

Fig. 75 is a vertical section showing the flame cavity in the slide, 
in the act of introducing coal gas at the upper part and inflaming 
it at the point of junction, between gas and air. 

The slide a contains a forked passage b communicating at the 
lower passage with the air inlet c, and at the upper passage with 
the funnel f, which are both in the valve cover d, which holds the 
valve against the engine face. The jet c has a flame constantly 
burning into the funnel, which becomes heated, with the effect of 
drawing a current of air through the forked passage when its ports 
are in proper position ; the direction of the current is shown by 
the arrows. The pipe j supplies coal gas which passes along the 
gutter i, cut in the cover and valve faces, into the forked passage 
c, and thence to the funnel f where it is inflamed and burns as 
shown. When the movement of the slide cuts off communication 
with the atmosphere, it also closes the gutter i and terminates the 
supply of coal gas from the pipe j, but the upper part of the forked 
passage contains gas ; a flame therefore flickers as shown. Just 
before b opens on the port l, fig. 76, the hole k, fig. 75, opens and 
the pressure from the explosion space causes a flow into b, forcing 
before it the gas contained in the hole, thereby intensifying the 
flame by making the gas pass more into the air and bringing about 
the equilibrium of the pressures. When b opens on l, the flame 
is a vigorous one, and at once fires the whole charge in the explo- 
sion chamber. Fig. 76 shows the slide with the port b at the 
moment of opening on l. Fig. 77 is an end elevation of the 
valve and cover, showing the ports and gutters dotted and lettered, 
position same as in fig. 76. The method is carried out completely 
and is a very perfect one indeed ; it is somewhat slow in action, 
depending as it does on a proper ventilation of the forked passage 
and the complete replacement of the burned products by fresh air 
before the gas can burn properly in the cavity. If the engine be 
run more rapidly than the draught of the funnel can clear out the 
passage from the burned gases, then the flame cannot be lit in it 
and an ignition will be missed. 

It is a method exceedingly successful when ignition is not 
required too frequently, but very troublesome and uncertain for 



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The Gas Engine. 



rapid ignition. The Otto and Langen engine only made 30 igni- 
tions per minute, and the Otto compression engine makes but 80 




FIG. 76.— Sectional Plan, Otto Igniting Valve. 



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Igniting Arrangements 



215 



ignitions per minute at full power ; its efficiency is good at these 
rates, but at 150 per minute it is too slow in action. 




> 

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& 

o 

o 



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W 

I 







Clertts Igniting Valve. — The method of igniting the charge used 
by Clerk is quite different from the other flame methods already 
described ; the difference is necessitated by the greater rapidity of 
ignition in engines with an impulse for every revolution. 

To ventilate the igniting port in the Otto and Hugon slides 
requires time, which cannot be given when the frequency of the 
ignition approaches 150 to 200 per minute. 



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216 Tlie Gas Engine 

To meet this difficulty the author has invented several methods 
both flame and incandescence, but the one to be described is 
that at present in use in his engines ; it is very reliable and rapid, 
as many as 300 ignitions per minute having been made with it 
experimentally, or at the rate of 5 ignitions per second. 

A portion of the explosive charge is allowed to pass from the 
motor cylinder through a regulated passage to a grating placed at 
the end of a cavity in the slide, and is there ignited by a Bunsen 
flame ; the grating prevents the passage back of the flame, and 
the mixture burns in the cavity without requiring the presence of 
the external atmosphere. At each end of the cavity there is a 
port opening to opposite sides of the valve, the one for lighting 
the gases streaming from the grating, the other for communicating 
with the interior of the cylinder at the proper time. The com- 
munication with the cylinder is not made until the outer port cuts 
off from atmosphere, and the flow of the gases is so regulated that 
while this is being done, the flame still continues to be fed by 
fresh supplies. It is evident that if too great a current be sent in, 
the pressure will soon become equal to that in the cylinder, and 
then the flow towards the cavity will cease and the flame become 
extinguished ; this is guarded against by proper proportioning of 
the flow by the check pin. The pressure in the cavity when its 
port opens on the cylinder port is still slightly less than that in the 
cylinder, and the gases from the cylinder enter and are ignited. 
By using gas and air already mixed in proper proportion, the ne- 
cessity of ventilating is removed, and it is made possible to ignite 
at the rate required by the system of impulse at every revolution. 
Without this it would be almost impossible to get a passage cleared 
out in time to allow of so frequent ignition, by a coal gas flame 
burning simply in air. It was first used by Clerk in an engine work- 
ing in February 1878, and has subsequently been used by Wittig 
and Hees and by Robinson in the Tangye engine. In the form 
here described it was first used by Clerk in November 1880. 

Fig. 78 is a sectional plan of the igniting slide and cover as 
well as the passage into the combustion space. The valve 1 con- 
tains the cavity 2, furnished at the ends with the ports 3 and 4 ; at 
the end 3 is placed the grating 5, communicating behind with 
the explosion port 6, by a small hole 7 and a gutter in the 



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217 



valve face, showing at fig. 78. A long pin 8 screwed into 
the end of the slide controls the gases entering the space behind 
the grating, and if need be can cut off communication altogether. 
When the valve is in the position shown in the drawing, the mix- 





Valve in position of flame lighting at external flame. 
Fig. 78.— Sectional Plan, Clerk Igniting Valve. 

ture is beginning to flow through the grating into the space 2, 
and is ignited by the Bunsen flame 9 lying up against the valve 
face. The Bunsen flame lies so close to the grating that im- 
mediately inflammable mixture comes, it is lighted before it can 



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218 



The Gas Engine 



get time to fill the cavity ; if allowed to accumulate in the cavity 
before lighting, a slight explosion ensues and a disagreeable report 
is produced. The flame at the grating burns in the cavity, dis- 
charging into the passage 10, and from thence to the atmo- 
sphere. The movement of the slide cuts off communication with 
the atmosphere, first on the Bunsen flame side, and then on the 




Internal flame exploding mixture. 
Fig. 79. — Sectional Plan, Clei k Igniting Valve. 

inside of the valve ; very shortly after, the port 4 opens on the port 
6 leading to the cylinder, and the gases then taking fire communi- 
cate the flame to the whole contents of the compression space. 
In fig. 79 the flame port in the valve is full open on the explosion 
port of the engine. The slide then moves past the port and back 



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Igniting Arrangements 



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to the first position, where the operations described are repeated 
and igniting again occurs. 

This arrangement is very rapid in action, and is capable of 
igniting with the utmost regularity at a rate so high as 300 times 
per minute, which is far in excess of the requirements of the 
engine Fig. 80 shows the Bunsen flame burning against the face 
of the valve, ready to ignite the gaseous mixture. 






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Bunsen mrher 



Fig. 80.— End Elevation, Clerk Igniting Valve. 

Bray tori s Flame Ignition.— The Brayton method of ignition 
has already been described shortly in the description of the engine. 
It is so beautiful and instructive that it merits further discussion. 

The action will be made clearer by describing a well-known 
laboratory experiment (fig. 81). 

A piece of wire gauze, a, held a few inches from the Bunsen 
lamp, &, the gas being turned on, will prevent the flame when lit 



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220 



The Gas Engine 



above it from passing back through the gauze to the burner. The 
gauze may be moved through a considerable distance from the 
Bunsen tube without extinguishing the flame. The mixture of gas 
and air streaming from the Bunsen passes through the gauze, and, 
although igniting above, the heat is so rapidly conducted away by 
the gauze, that the flame cannot pass through its interstices back 
to the lower side. If an explosive mixture be confined under say 
30 lbs. per square inch pressure in a vessel, and a pipe from it 
(fig. 82) leads to a pair of perforated plates with gauze between 
them, a, then the cock b being opened gently (the valve e being 
previously open), the mixture will stream through the plates into 




Fig. 81.— Bunsen Flame burning above Gauze. 

the atmosphere, and, if ignited, will burn at a without passing 
back. If the cock b is opened suddenly a greater rush of flame 
will occur, diminishing again if it is partly closed. 

So long as enough mixture passes to preserve alive the flame 
at a, then any increased quantity passing from the reservoir will 
be burned ; the little flame increasing or diminishing as the 
opening of the stop- cock valve is increased or diminished. 

The action of the ignition in the Brayton engine is exactly 
similar. The pressure on the flame side of the grating is slightly 
below that existing on the other side ; the stream of cold gases 



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entering the engine cylinder immediately becomes flame on the 
grating, and so expands, the volume of flame being changed as 
required by the valve action of the engine. 

This method is most successfully carried out in the Brayton 
engine. The lack of economy is not due to the ignition, but to 
the use of it under unsuitable circumstances. Without doubt this 




Plan of grating. 

Fig. 82.— Brayton Grating and Valve. 

system, in a better combination, will come largely into use in 
future and larger gas engines. It is unsuited for cold cylinder 
explosion engines, but admirably adapted for hot cylinder com- 
bustion engines of the second type. 



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222 



The Gas Engine 



(3) Incandescence Methods. 

The ignition of explosive mixtures by contact with heated 
metallic surfaces has often been proposed, first by the late Sir 
C. W. Siemens, and after him by the American, Drake. Dr. 
Siemens, in one of his gas engine patents, proposes to ignite the 




Fig. 83. —Sectional Plan, Clerk Incandescent Platinum Igniting Valve. 

mixture by passing it through an iron tube, which is heated to red- 
ness by a flame outside of it. 

Drake constructed an engine in which the ignition was effected 
in a similar manner. The difficulty is found in the rapid oxidation 



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Igniting A rrangements 



223 



of the tube, and the consequent necessity for frequent renewal. 
Frequent attempts have also been made to heat a portion of the 
interior surface of the cylinder, so that at a suitable time the mix- 
ture might be exposed to it and fired. 

The first arrangement of incandescent ignition successfully 
applied to a compression engine is the invention of the author, 
and is described in his patent, No. 3045, 1878. It was used in an 
engine exhibited at the Royal Agricultural Society's Show, Kilburn, 
in 1879 (July). 

Clerks Igniting Valve, — Fig. 83 is a sectional plan of this 
valve in position. Fig, 84 is a separate view of the valve looking 
upon the face, and fig. 85 is the platinum cage, full size, taken out 
of the valve. 



Fig. 84.— Face of Valve with Platinum Cage. 




Fig. 85.— Platinum Cage. 

The platinum cage consists of a box of platinum plate, with 
numerous platinum ribs running across it. They are secured by 
rivets running completely through, small platinum washers serving 
to keep the plates at equal distances. The valve receives this 
cage in a cavity, and it is tightly packed in its place with asbestos 
and slate packing, a covering plate screwed down upon it securing 
the whole in position. To start the engine, the reservoir contain- 
ing gas and air under pressure is opened ; the small tap, 1, then 
opened allows mixture to flow through the diaphragm 2 (made 
like the Brayton grating), and the mixture is ignited at the 
small door 3, which is then closed. The flame flows through the 



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224 



The Gas Engine 



platinum cage, heating up its plates to a white heat in a few 
seconds. On opening the starting cock of the engine, it moves, 
and brings the igniting port 4, on the cylinder port 5, at the same 
time opening on the port 6, in the cover, leading into the cavity 7. 
The mixture in the cylinder then rushes through the cage, becom- 
ing ignited, and the explosion reaches the cylinder ; the cavity 7 

is so proportioned that each igni- 
tion sends a measured quantity 
of flame through the cage into it ,■ 
the heat of the explosion at every 
turn therefore supplies heat to 
the platinum. This added heat 
is sufficient to keep it at a white 
heat. So long as the engine is 
supplied with gas it gets an ig- 
nition at every revolution, and a 
portion of that heat goes to the 
platinum to make up for loss by 
conduction. The heating flame 
used in starting the engine is 
dispensed with immediately on 
starting, and the engine runs con- 
tinuously without outside flame. 
This method is exceedingly reli- 
able and rapid, but is not suited 
for the governing arrangements 
of small engines. 

Siemens' Tube Method.- -Fig. 86 
is an arrangement of Siemens' 
method, as used by Mr. Atkinson 
in his * Differential ' engine, ex- 
hibited at the Inventions Exhibi- 
tion. The wrought iron tube 1 is 
heated by the Bunsen flame 2, 
the non-conducting casing 3 pre- 
venting loss of heat ; the piston at the proper time uncovers the 
hole 4 into which the tube is screwed, and the mixture entering 
under pressure becomes ignited. In other engines the tube is 




Fig. 86.— Hot Tube Igniter. 



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Igniting A rrangements 225 

caused to communicate with the cylinder by a valve. This modi- 
fication is exceedingly simple and works well ; care must be taken 
to avoid overheating, or the explosion may rupture the tube. It 
is inexpensive and easily renewed when disabled by oxidation. 

(4) Methods depending on Catalytic and 
Chemical Action. 

The well-known property of spongy platinum of causing the 
spontaneous ignition of a stream of hydrogen or coal gas directed 
on it in air, has been proposed as a means of ignition by Barnett 
( 1 838). In the arrangement he describes, the platinum is contained 
in a little cup screwed into the cylinder cover, and the compression 
of the mixture causes its ignition by contact 

Platinum, however, soon loses this property, and the action is 
at best too slow for use. 

All flame methods of course depend on chemical action, but 
one proposal has been made, to use the property possessed by 
phosphorated hydrogen of igniting spontaneously in contact with 
air. The phosphoretted hydrogen is conducted in small quantity 
into the mixture to be exploded at every revolution, and its com- 
bustion causes ignition. 

This proposal has never been carried out in practice. 

Summary, — To the author's ' knowledge no other systems 
of ignition have been proposed ; the flame methods are best 
suited for small gas engines and will probably continue in use. 
Considerable improvements may still be effected in ignition valves, 
and it is possible that external flames may be entirely done 
away with in future engines. It is somewhat humiliating to the 
inventor to watch a powerful gas engine at work, developing say 
30 horses, and to know that he can at once change the whole 
and make the engine powerless by blowing out the external flame. 

A combination of flame and incandescence methods will doubt- 
less overcome this difficulty, and make the gas engine act without 
visible flame and without the danger of extinction from draught, 
to which the present igniting flames are subject. 

It is improbable that either the first or fourth methods will 
again find favour, the electric methods give too much trouble and 
are at best uncertain. 



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226 77ie Gas Engine. 



CHAPTER IX. 

ON SOME OTHER MECHANICAL DETAILS. 

A good working cycle and good igniting arrangements are the two 
most important factors in the successful working of a gas engine, 
but there are other matters whose importance is only secondary 
to those. The governing gear, the oiling gear, and the starting 
gear, are of the greatest importance. 

These matters will now be described. 

The Governing Gear, — In the earlier gas engines, including 
Lenoir and Hugon, the governing was attempted precisely as is 
done in the steam engine, the source of power being regulated 
by throttling. A centrifugal governor acted upon a throttle valve 
regulating the gas supply, diminishing it when the speed became 
too great and increasing it when the speed fell. 

This was a very bad and wasteful method, as the engineer will 
at once recognise from his knowledge of the properties of explosive 
mixtures. 

The limits of change allowable in the proportions of gaseous 
explosive mixtures are very narrow, the gas present ranging from 
\ to T V of the total volume. A mixture containing \ of its volume 
of coal gas in air has just sufficient oxygen to burn it and no 
more ; any further increase of gas will pass away unburned, there 
being insufficient oxygen present for its combustion. 

This is therefore the richest mixture which can be used with 
any economy. 

A mixture of air and gas containing ^ of its volume of gas is 
in the critical proportion ; any further dilution, however slight, will 
cause it to lose inflammability altogether. The governor may 
act in changing the proportion of gas and air between those limits, 
that is, the explosion may be so reduced by dilution that it gives 



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On some oilier Mechanical Details 



227 



only naif the power per impulse obtainable with the strongest 
mixture. 

Any further dilution causes the engine to miss ignition al- 
together, and discharge the gas it has taken into the exhaust pipe, 
without obtaining any power from it. If, therefore, the governor 
acts by throttling, the valve is only closed enough to cause the 
mixture to be so weak as to miss fire ; as soon as that point is 
reached the valve will be closed no further, because at that point 
the speed of the engine will cease to increase. Fig. 7, p. 14, shows 
the governor in action upon a Lenoir engine. 



horn 




Fig. 87. — Section showing Otto and Langen Governor. 

In modern compression engines the great loss of gas occasioned 
by throttling is avoided by never diluting the mixture. Instead of 
keeping up the same frequency of impulses but of less power, as 
done in the steam engine, the gas is either full on or full off, 
that is, the governing is effected by diminishing the frequency of 
the impulses instead of diminishing their power. 

In the specification of the Otto engine, 1876 (2081) the 
governing is described as being effected by reducing the power 
of the explosion. This is more impracticable in the Otto engine 

Q2 



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228 



The Gas Engine 



than in the Lenoir, because, owing to the dilution of the charge by 
the exhaust gases or air, the range of change in mixture is smaller. 
The strongest mixture does not exceed i of coal gas in 8 of other 
gases. 

Governing — Otto and Langen Engine. — In this engine, in its 
latest and best form, the governing is effected by missing impulses. 
When the engine has received an impulse, the increase in speed 
causes the governor to move a lever which disengages a pawl from 
a ratchet, and so prevents the piston being raised and the charge 
drawn into the cylinder. When the speed has fallen sufficiently 




Vvs/ 



Fig. 88.— Otto and Langen Governor, showing Pawl and Ratchet. 

the lever liberates the pawl, and the piston is then raised, taking 
in the charge and exploding it Fig. 87 is a sectional elevation of 
the governing arrangements. The auxiliary shaft 1 is driven from 
the main shaft 2 by the clutch 3, but the crank 4 and shaft 1 re- 
ceive motion from 2 only by means of the pawl 5 falling into the 
ratchet 3 ; so long as the governor lever 7 remains in the position 
shown, the pawl is kept from engaging and the piston and valve 
remain at rest ; so soon as the governor lever 7 liberates 
the pawl, then it falls into the ratchet wheel by a spring and the 



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On some otlier Mectumical Details 229 

auxiliary shaft receives one turn ; the crank 4, connected to the 
lever 8 (fig. 88), lifts the rack, and the piston takes in its charge ; 
at the same time the valve opens to gas and air, then, when 
the piston is full up, brings on the igniting flame. The ex- 
plosion occurs and shoots up the piston, which on its down stroke 
accelerates the motion of the power shaft, and if the limit of speed 
is exceeded, the governor lever again interposes and prevents the 
charge and explosion till the speed falls. 

When running without any load, the two horse engine tested 
at Manchester by Clerk required only 6 ignitions per minute, con- 
suming, including side lights, about 25 cubic feet per hour. The 
shaft therefore ran as many as 15 revolutions merely by the power 
stored in the fly-wheels. 

The governing is effective but irregular. 

Governing — Otto Engine. — The speed of the Otto compression 
engine is governed by diminishing the number of impulses given 
to the crank ; whenever the normal rate is exceeded, the governor 
so acts that the gas supply is completely cut off for one or more 
strokes of the engine, no impulse being given till it falls again. 

One arrangement very commonly in use is shown at fig. 89. 

The cam 1 upon the auxiliary shaft 2 is arranged to strike the 
wheel 3 upon the lever 4, opening the gas valve 5 at the begin- 
ning of the stroke and keeping it open till the end of the stroke 
of the piston ; the gas passes from the gas valve by a passage to the 
holes in the slide, when it streams into the air current entering the 
engine by the admission port Whenever the speed becomes high 
enough, the governor 6 by the lever 7 shifts the position of the cam 
1 upon its shaft, so that the wheel 3 does not strike it; the gas valve 
5 therefore remains shut for that stroke, and the piston draws air 
alone into the cylinder. When the piston returns and compresses 
the charge, the igniting flame enters as usual, but there being 
no explosive mixture there, the piston moves out again without 
impulse, expanding and discharging, charging and compressing an 
uninflammable charge, till the reduction of speed calls again for an 
impulse ; the first ignition after the engine has made several re- 
volutions without gas is always more powerful than the normal 
one, because no exhaust gases being there the charge mixes in the 
space with pure air and is not heated previous to explosion. 



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230 



The Gas Engine 



The arrangement in different Otto engines varies from this, but 
the principle is always the same. 

Fig. 90 is a recent and very clever governing arrangement as 
used in the smaller Otto engines. 




Fig. 89. — Otto Governor and Connecting Gear. 

The ordinary governor is entirely dispensed with, and the valve 
itself carries a pendulum which governs. 

The pendulum 1, hanging from the pin 2 in the slide valve 3, 
carries the long steel blade 4, which usually strikes the stem 5, and 
opens the gas valve at the same time as the slide opens to the air. 
Whenever the speed is exceeded, however, the motion of the valve 



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On some other Mechanical Details 



231 



in the direction of the arrow, exceeding a certain rate, the pendu- 
lum 1 is left behind and depresses the steel blade 4, which therefore 
misses the gas valve stem and for that revolution no gas enters. 
So long as the speed is sufficient to swing back the pendulum no 
gas enters ; as soon as it is insufficient to cause the pendulum to 
leave its resting position against the valve, then gas is admitted. 

As the pressure of the edge of the steel plate upon the valve 
stem is in direct line with the centre of the pin upon which the 
pendulum hangs, there is no tendency to move it, that is, the 
governor does not furnish the power to open the gas valve. In 
all the Otto governing arrangements this principle is adhered to ; the 




Fig. 90.— Otto Pendulum Governor. 

governor never furnishes the power to move the gas valve, but 
only signals to the engine the proper time to give the motion, 
the motion being always taken from the engine itself. 

In electric light engines, which must give the impulse for every 
two revolutions with some change of power, the gear is modified ; 
instead of complete cut-off as first described, the cam upon the 
shaft is made in several steps, so that the wheel upon the gas lever 
is shifted from one to another as shown in fig. 91, where 1 is the 
gas cam, and 2 is the wheel upon the gas lever. Those steps are 
made to diminish supply of gas as much as possible without miss- 
ing ignition, so that within narrow limits of changing load, the 



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232 



The Gas Engine 



engine may retain its frequency of impulse. Whenever this 
range of permissible variation is exceeded, the wheel slips entirely 
off the cam, and the engine then governs in the ordinary manner. 




Fig. 91. — Otto Electric Light Governor. 

Gwerning — Brayton and Simon. — In the Brayton gas engine 
the governing was effected precisely as in the best steam engines, 
by varying the point of cut-off. The entering flame was cut off, 
sooner or later, as determined by the governor of the engine ; and 
the admission of gas and air to the pump was simultaneously 
regulated, the amount entering being diminished to keep the 
pressure in the reservoir constant. The diagram, fig. 45, p. 158, 
shows that the variable cut-off acted well. 

Fig. 92 shows the governor of the petroleum engine. 

The cam 1, which opens the admission air valve on the motor 
cylinder, is made tapering, so that the point of cut-off becomes 
earlier and earlier as it slides in the direction of the arrow. 

The supply of air was thus diminished. In this engine the 
supply of petroleum could only be diminished by hand, two screws 
on the oil pump, when screwed upwards, altering the connecting 



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On some other Meclianical Details 



233 



rod between the plunger and the eccentric, giving more or less 
free movement, and thereby diminishing the throw of the pump. 

The air supply to the engine was not diminished, so that the 
pressure in the reservoir increased, and was blown off at a safety 
valve placed upon the engine. This was a wasteful method. 

The regularity of this engine in running was very great, being 
far superior to any of the modern compression engines. It was, 
however, not at all economical. 

Simon's engine presented no new feature in its governing 
arrangements. They were quite similar to Brayton. 




Fig. 92. — Brayton Governor. 

Governing — Clerk Engine. — The governing gear now used 
upon this engine is the design of Mr. G. H. Garrett, Messrs. 
L. Sterne & Co.'s works' manager. It is shown at figs. 93 and 94. 

It consists of a gridiron slide placed between the upper and 
lower lift valves. So long as the engine is at full power, the slide 
1, fig. 93, is moved by the lever 2, fig. 94, from the ignition slide 
of the engine already described, and remains open during the 
forward stroke of the displacer piston. 

The charge of gas and air therefore enters during the whole 
stroke, and is sent into the motor cylinder to be compressed and 
ignited at the proper moment. If, however, the load is lessened, 
and the speed increases, and the governor 3 acts, it moves the 
lever 4, which then catches the lever 2, and prevents the spring 5 
from taking the slide 1 back and opening it. The displacer then 
discharges its contents into the motor cylinder, but on its next 
out-stroke, the valve 1 being closed, it gets no charge but the 



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234 



The Gas Engine 




G 




■^ 



a- 



FlG. 93.— Sections and Plan, Governor Slide, Clerk Engine. 




a 



FlG. 94.— Clerk Engine showing Garrett Governor Gear. 



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On some other Medianical Details 



235 



piston moves out, forming a partial vacuum behind it. The motor 
cylinder, therefore, receives no charge from the displacer cylinder, 
and the motor piston compresses and expands alternately the 
burned gases behind it, while the displacer piston moves out and 
in, expanding and compressing likewise. This goes on till the 
governor signals reduction of speed, and disengages the lever 2, 
by pushing down the lever 4, so that the spring 5 opens the slide 
1, and the engine gets a charge. 

This method works very well and economically ; it is necessi- 
tated by the clearance space unavoidable in the Clerk engine 
between the motor and displacer cylinders. If gas were cut off as 
in the Otto, that space filled with mixture would be lost every time 
the governor acted. 

Governing — Tangye Engine. — Messrs. Tangye's gas engine is 
now controlled by a very ingenious governor, the invention of 




Tangye Engine. 



Mr. C. W. Pinkney. It is shown at fig. 95. The rod 1 1, moved 
to and fro by an eccentric, carries with it the bracket 2, into 
which is fixed the pin 3 ; on this pin the lever 4 is swung, and 
moves to and fro with the bracket ; the lever is pressed gently 
downwards by the spring 5, and the lower part of the lever is 
formed into an incline at 6, so that as it moves the spring presses 
it against the roller 7. So long as the engine does not exceed its 
proper speed, the lever 4 does not rise above the position shown 



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236 Tfte Gas Engine 

in the figure when it is moving in the direction of the arrow, and 
accordingly its knife edge end strikes the lever 8 and, acting 
through the intermediate links, opens the gas valve 9. The 
engine gets its charge of gas every time the gas valve opens. If 
the speed becomes too great, then the upward velocity given to 
the lever 4 by the stationary roller 7 forcing against the incline is 
such that the knife edge lever 4 rises above the end of the lever 
8, and the gas valve remains closed. When the speed falls 
sufficiently the lever 4 again strikes the lever 8 and opens the gas 
valve. 

The incline governor works well and is exceedingly sensitive 
to change in speed : by altering the compression upon the spring 
5 the speed of the engine can be varied. 

Oiling Gear. — In the steam engine the comparatively low 
temperature of the steam within the working cylinder and the 
fact of its condensation upon the walls and piston renders the 
task of lubricating an easy one. The lubrication need not be 
absolutely continuous and the nature of the oil may vary much 
and no harm is done. 

With the gas engine, the intense flame filling the cylinder at 
every stroke quickly destroys the film of oil with which it is 
covered, and necessitates its continuous renewal. 

If animal oil be used, its decomposition leaves considerable 
charred matter, which speedily coats the piston and cylinder, 
causing friction and danger of cutting. A good hydrocarbon, on 
the other hand, even when subjected to intense heat, decomposes 
into gases without leaving any appreciable amount of carbon : 
mineral oils should therefore alone be used for the cylinder and 
ignition slide. 

The amount of oil required for these parts is small per day, 
but it must be regularly applied ; the burned film removed from 
the surface of the cylinder at every explosion must be regularly 
replaced or abrasion of the surfaces would speedily ensue. 

In the Otto engine the oil required is supplied during the whole 
action of the engine ; it commences with the movement of the en- 
gine, continues so long as it is running, and stops when motion ceases. 

Fig. 96 shows the Otto oiling cup, one of which is placed, as 
shown in the drawing, fig. 97, at the middle of the cylinder to 



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On some otfier Mecfianical Details 



237 



lubricate the piston and slide ; the pipes 4 and 5 lead to the 
piston and slide. 

The pulley 1 is driven slowly from the auxiliary shaft by a 
strap, and as it rotates it carries the wire 2 round on the pin 3, 




Fig. 96.— Illustration of action of Otto Oiler. 

fig. 96, alternately dipping into the oil and wiping it oft" to the 
pin, from whence it drops into the trough 4 and runs by a hole 
into the tubes. The amount of oil so discharged can be regulated 
by the diameter of the wire. The oil flows along the pipes 4 and 




Fig. 97. — Arrangement of Otto Oiler. 

5, fig. 97, and drops into holes at 6 and 7, the one oiling the piston 
every time the trunk comes forward, the other oiling the valve by 
suitable gutters. 

The Clerk oiling cup is shown at fig. 98 ; it is not automatic. 
The screw pin 1 is set in a position marked for each cup, the 



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238 



The Gas Engine 



motor cylinder cup giving 15 drops per minute, and the valve cup 
5 drops per minute. 

In both Otto and Clerk engines the slide valves should be 
taken out and cleaned once a week. The charred oil should be 
carefully scraped out of the gas gutters and igniting ports ; the 
piston also should be drawn occasionally, once in three months 
being sufficient The interior of the cylinder should then be 
cleaned, especially the explosion space. The Otto exhaust valve 
should be taken out every week and cleaned. The Clerk upper 




Fig. 98.-ClerkOilCup. 

and lower lift valves require cleaning once every month if the 
engine is hard worked. 

In working gas engines the two points requiring attention are 
oiling and cleaning. Never run the engine, without oil, and clean 
regularly. Never start without seeing that the water circulation 
is open. 

Starting Gear. — Till very lately, gas engines of every power 
were started by manual labour ; in small machines the inconveni- 
ence is not great, but with large engines such as those giving 
from 20 to 50 indicated horses when at full power, the friction 
is so considerable that difficulties arise. It is difficult to reduce 
friction so much that a large machine may be turned with suffi- 
cient velocity by a couple of men, to get a sure and easy start. 

The Brayton petroleum engine was the first to use reservoirs 



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239 



for retaining sufficient air for starting, but they were so faultily 
constructed, that leakage and loss were so frequent that the appa- 
ratus was of little use. Many arrangements have been described 
by inventors, but no starting gear found its way into public use 
till that invented by the present author in the end of 1883. The 
Clerk engine was the first to use starting gear in public, at the 




Fig. 99. — Clerk Starting Gear. 

beginning of 1884. Since then over 100 engines have been fitted 
and are at daily work with it. 

The Otto engine speedily followed Clerk's in the application 
of gear, and after them came Tangye and Atkinson. 

Starting Gear — Clerk Engine. — The starting gear used in the 
Clerk engine is shown at figs. 99 and 100. Its action is as follows. 



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240 



The Gas Engine 



The flap, valve i, in the communicating pipe between the displacer 
and motor cylinders is closed, while the engine is running, by the 
handle 2 ; the gases in the displacer are thus prevented from 
entering the motor cylinder, and are compressed through the 
valve 3, which is an automatic lift, into the reservoir 4, by the stop- 
valve 5, which must of course be open. 

The ignition being stopped, the speed of the engine falls, and 
the flap is opened for a few strokes, to allow the speed to get up 
again. It is then closed again, this being repeated till the reservoir 
4 is charged with a mixture of gas and air at 60 lbs. per sq. in. 
above atmosphere. Five minutes gives ample time to charge 




Fig. 100.— Clerk Starting Valve. 

from completely empty to 60 lbs. Three minutes suffice if the 
charge has not been completely taken from the reservoir during 
the previous start. The relief valve at 6 prevents charging above 
60 lbs. per sq. in., the excess blowing into the exhaust pipe. 
When the reservoir is charged the stop valve 5 is screwed down 
and the charge is retained in the reservoir till wanted. The 
reservoir is made of steel, the sides being i in. thick and the ends 
§ ; it is welded throughout, and is tested before leaving the works 
at 1000 lbs. per sq. in. 

The screw down valve 5 and the joint where it is screwed 



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241 



into the end form the only joints for loss by leakage ; numerous 
joints must be avoided, as it is often necessary to leave the 
reservoir charged for weeks ; the faintest leakage would in so long 
a time lose the contents, and so the start would require to be 
made by hand 

The reservoir is so pressure tight, when made as described. 




Fig. 101.— Otto Starting Gear. 

that the author has left one standing for six weeks and started the 
engine with ease with what remained. 

The starting is effected as follows : 

The engine is placed in such position that the motor crank is 
on the full in centre. The displacer is therefore half forward, the 
reservoir stop valve is opened, the Bunsen burner is lit, and the 
gas cock of the engine set at the starting mark. The starting 
handle 7 is then moved in, opening the valve 3, fig. 100, the gases 

R 



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242 The Gas Engine 

entering press forward the displacer piston and fill the compres- 
sion space of the engine, pressing forward the motor piston when 
its crank comes off the centre. The starting handle is then let 
go, and the motor piston runs over its ports discharging the con- 
tents both of motor and displacer to atmosphere. The engine has 
thus received a double impulse, one in each cylinder ; it is enough 
to bring round the piston, compress the mixture and get an igni- 
tion. One opening or at most two openings of the starting valve are 
enough. The reservoir contains enough to give six successive starts. 

After starting, the reservoir should be again charged and closed 
so that it may be ready when required. 

The gear works very well and is easily handled. 

To those accustomed to see gas engines started by hand, it is 
somewhat astonishing for the first time to watch a large machine 
move away at once by a mere finger touch upon a valve. 

Starting Gear — Otto Engine, — The starting gear used in the 
Otto engine is shown at fig. 101. It consists of the reservoir i, 
the charging and starting valve 2 and a stop valve. The charging 
valve is loaded so that it does not open with a pressure less than 
40 lbs. per square inch, as it communicates with the compres- 
sion space 4. It follows that the compression of the charge in the 
cylinder does not lift it, but as soon as the gases explode, the 
pressure lifts the valve, and the reservoir gets filled slowly with 
burned gases. If the valve is left open long enough the pressure 
will rise to within 40 lbs. of the maximum explosion pressure, that 
is, about no lbs. per square inch above atmosphere. The stop 
valve being screwed down, the gases are retained ready to start 
the engine when wanted To start, the stop valve at the reservoir 
is opened, and the engine crank placed in such position that it is 
off the centre and on its impulse stroke. The gases then pass 
through the valve 2 into the cylinder 4, and the valve 2 closes at 
the end of the stroke actuated by the cam 3. One impulse is 
thus given and is repeated at the proper time by the action of the 
cam 3 upon 2, through the intermediate lever. The pressure re- 
quired is high, because only one forward movement of the piston 
is available for every two revolutions of the engine. The twin 
engine therefore starts more easily than the ordinary type of Otto. 
This gear also works well ; it was patented before the Clerk gear, 
but was later in being introduced into public use. 



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243 



CHAPTER X. 

THEORIES OF THE ACTION OF THE GASES IN THE MODERN 
GAS ENGINE, 

The general principles developed in this work explaining the 
causes of the economy of the modern gas engine were first enun- 
ciated by the author in a paper read before the Institution of 
Civil Engineers in April 1882. 1 

He then classified gas engines in three great groups : 

Type 1. — Explosion, acting on piston connected to crank. (No 
compression.) 

Type 2. — Compression, with increase of volume after ignition, 
but at constant pressure. 

Type 3. — Compression, with increase in pressure after ignition, 
but at constant volume. 

It was proved that under comparable conditions the relative 
theoretic efficiencies of the three types were 

Type 1 = 0*21 
Type 2 = 0*36 
Type 3 = 0-45 

It was also shown that in the actual engines the real efficiency 
could not be so high as the theoretic, mainly because of the large 
proportion of heat lost through the sides of the cylinder, by the 
exposure of the flame which filled the cylinder to the comparatively 
cold enclosing walls. A balance sheet was given showing the 
disposal of 100 heat units by a compression engine. Of the 100 
heat units, 17*83 were converted into indicated work, 29-28 were 

1 The Theory of the Gas Engine,' by Dugald Clerk : Minutes, Institute Civil 
Engineers, London. Paper No. 1855. April 1882. 

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244 The Gas Engine 

discharged with the exhaust gases, and 52-89 units passed through 
the sides of the cylinder into the water jacket. 

The economy of the Otto engine over its predecessors, the 
Lenoir and Hugon engines, was clearly proved to be due to the 
fact of its using compression previous to explosion. 

These conclusions were very generally accepted by scientific 
and practical men who had studied the subject, and in February 
1884 the late Prof. Fleeming Jenkin, then Professor of Engineering 
at the University of Edinburgh, delivered a lecture at the Institu- 
tion of Civil Engineers in London, on * Gas and Caloric Engines.' l 
He had recalculated the efficiencies due to compression, with the 
result of corroborating the present writer's conclusions. He 
stales : 

* If I were to compress gas to 40 lbs., a pressure which is used 
not unfrequently, the theoretical efficiency would be 45 per cent 
We actually get something like 24 or 23 per cent. ; we know that 
one-half of the heat is taken away by external cooling. Thus we 
find a very close coincidence between the calculated efficiency of 
those engines and that which we actually obtain, only we throw 
away about one-half of the heat in keeping the cylinder cool 
enough to permit lubrication. If we compress to 80 lbs. we have 
a theoretical efficiency of 53 per cent If we do not compress at 
all, as Mr. Clerk has told you, we have a theoretical efficiency of 
only 21 per cent, so that we have it in our power to increase the 
theoretical efficiency very greatly by increasing the pressure of the 
gas and air before ignition. I have no doubt that the great gain 
of efficiency in the Clerk and Otto engines is really due to the 
fact of the compression ; this being done in a workmanlike way 
and carried to a very considerable point.' 

The advantages of compression couid not be stated with more 
clearness and truth. 

In the same year there was published in Paris an able work 
entitled * Etudes sur les Moteurs k Gaz Tonnant,' by Professor Dr. 
AimeWitz, of Lille, in which the theoretic efficiencies of the different 
types of cycle are calculated for a maximum temperature of ex- 
plosion of 1600 C, and temperature before explosion of 15 C. 

1 ' Heat in its Mechanical Applications ' : Institute Civil Engineers Lectures, 
Session 1883-84. 



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TJwories of Action of Gases in Modern Gas Engine 245 

He adopts the same classification as the present writer did in 
1882, and finds the efficiencies : 

Type 1=028 
Type 2 s= 0-38 
Type 3 = 0-44 

which are almost identical with the author's figures. 

He also arrives at the conclusion that compression is the great 
source of economy in the modern gas engine. At p. 53 he says : 
4 1 find myself again in agreement with Mr. Dugald Clerk when he 
affirms that the success of Otto is due to compression alone, and 
not to the extreme dilution of the explosive mixture in the pro- 
ducts of the combustion of a precedent explosion/ 

He then proceeds to quote from the present writers paper, and 
adheres to the statement that — 

4 Without compression previous to ignition an engine cannot 
be produced giving power economically and with small bulk.' 

Compression previous to ignition gives two great advantages : 

(1) A thermodynamic advantage (improved theory of the 
cycle) ; 

(2) Higher available pressures and smaller cooling surfaces 
— the joint result being an economy in practice nearly fourfold 
that of the old non-compression engines. 



Mr. Otto's Theory. 

Previous to 1882 the nature of the improvement obtained by 
compression was imperfectly understood, and this notwithstanding 
the very clear, though qualitative, statements of Schmidt, Million, 
and Beau de Rochas. An erroneous theory of the cause of the 
economy of the Otto engine was widely circulated and gained 
considerable support. 

It was enunciated in Mr. Otto s specification of 1876, No. 2081, 
and it was and is still, so far as the author is aware, supported by 
men so distinguished as Sir Frederick Bramwell, Dr. Slaby of 
Berlin, Prof. Dewar of the Royal Institution, and Mr. John 
Imray. 



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246 TJte Gas Engine 

According to Mr. Otto, all gas engines, previous to his patent 
of 1876, obtained their power from the explosion of a homoge- 
neous charge of gas and air. By the explosion excessive heat was 
evolved, and the pressures produced rapidly fell away ; the exces- 
sive heat was rapidly absorbed by the enclosing cold walls. 

This caused great loss and gave very wasteful engines. Two 
methods were open to obtain better economy : 

1st, by using a very rapid expansion, so that the heat had but 
little time to be dissipated ; 

2nd, by using slow combustion ; that is, by causing the in- 
flammable mixture to evolve its heat slowly, so that the production 
of excessive temperatures and pressures was avoided. 

By the first method all the heat was supposed to be evolved at 
once, and a high temperature was produced : by the second 
method the heat was evolved gradually so as to give a low temper- 
ature and pressure which was sustained throughout the stroke, 
and which was advantageously utilised by the piston while moving 
at a moderate speed. Mr. Otto states that this gradual evolution 
of heat may be produced by stratifying the charge of gas and air. 
Instead of using the homogeneous charge of Lenoir and Hugon, 
Mr. Otto uses a charge which he states is not homogeneous but 
heterogeneous. He affirms that his invention lies in the method or 
process of forming this stratified charge in a gas-engine cylinder, 
and that, in addition to the explosive mixture, there must be present 
in the cylinder a mass of inert gas which does not burn but which 
serves to absorb the heat of the explosion and prevent the loss 
which would otherwise occur by the cooling effect of the cylinder 
walls. 

The ' inert ' gas may be either air alone which is capable of 
supporting combustion, or the products of combustion which are 
incapable of supporting combustion, or a mixture of both. It is 
not sufficient that a mere film of this inert gas be present ; there 
must be what is termed a ' notable ' quantity. 

Mr. Otto proposes to form this heterogeneous or stratified 
charge by first drawing into the cylinder a charge of air alone ; 
and second, a charge of explosive mixture, or by leaving in the 
cylinder a sufficient quantity of the products of a previous com- 
bustion to form a ' notable ' quantity of inert diluent. 



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TIteories of Action of Gases in Modern Gas Engine 247 

The compression space in the Otto engine is supposed to con- 
tain a sufficient volume of burned gases to form the inert diluent, 
so that the whole stroke of the piston is available for taking in the 
explosive charge. 

Suppose the piston to begin its charging stroke : the coal-gas 
and air mixture flows into the cylinder through the inlet port and 
mixes to some extent with the inert gas already in the space ; but 
the mixing is incomplete, and at the piston itself the charge is 
supposed to consist entirely of exhaust gases. So that, while 
the charge at the igniting port is readily explosive, that at the 
piston is not explosive at all, and between the igniting port and 
the piston the composition of the charge varies from point to 
point. 

This l arrangement of the gases ' is supposed to be retained 
during compression, and exist at the moment of explosion. The 
compression space contains a * packed charge,' which consists of 
an explosive mixture at the one end, and between the explosive 
mixture and the piston a cushion of inert fluid, which is uninflam- 
mable and serves the double purpose of relieving the piston from 
the shock of explosion and absorbing heat which would otherwise 
be lost by conduction. 

By this device, heat is gradually evolved. The flame originated 
in the port burns at first with great energy and spreads from one 
combustible particle to another, more and more slowly as it ap- 
proaches the piston, where the particles are dispersed more and 
more in the inert gas. The mixture is so arranged that this burn- 
ing lasts throughout the whole stroke, and is complete very shortly 
before the exhaust valve opens. 

The entire cylinder is never completely filled with flame, but 
the charge at one end has burned out before the flame arrives at 
the other end. 

Dr. Slaby comes forward in support of this hypothesis in an 
interesting report published as an Appendix to Prof. Fleeming 
Jenkins' lecture already referred to. 

Dr. Slaby states : ' The essence of Otto's invention consists in 
a definite arrangement of the explosive gaseous mixture, in con- 
junction with inert gas, so as to suppress explosion (and neverthe- 
less insure ignition). 



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248 The Gas Engine 

4 At the touch hole, where the igniting flame is applied, lies a 
strong combustible mixture which ignites with certainty. The 
flame of this strong charge enters the cylinder like a shot, and 
during the advance of the piston it effects the combustion of the 
farther layers of dispersed gaseous mixture, whilst the shock is 
deadened by the cushion of inert gases interposed between the com- 
bustible charge and the piston. 

'The complete action takes place in a cycle of four piston 
strokes. The first serves for drawing in the gases in their proper 
arrangement and mixture ; the second compresses the charge ; 
during the third the gases are ignited and expand ; and finally, 
by the fourth the products of combustion are expelled. The 
essential part of the working is performed by the first of these 
strokes, by which the charge is drawn in and arranged, first air, 
then dilute combustible mixture, and finally strong combustible 
mixture. This arrangement is obtained by the working of the 
admission slide. Moreover, after discharge of the products of 
combustion, a portion remains in the clearance space of the 
cylinder, and this constitutes the inert layer next the piston. By 
this peculiar arrangement of the gases, the ignition and combus- 
tion above described are rendered possible, whilst the products of 
previous combustion form a cushion, saving the piston from the 
shock of the explosion of the strongly combustible mixture at the 
farther end of the cylinder.' 

Having stated the essence of Otto's invention, Dr. Slaby pro- 
ceeds to compare the Otto and Lenoir indicator diagrams, to show 
that the Otto diagrams prove that the above actions occur in the 
engine. He finds that the Otto expansion line is somewhat above 
the adiabatic line, and that the Lenoir expansion line is below it. 
That is, the Otto diagram gives evidence of heat being added or 
combustion proceeding in the cylinder during the whole expansion 
stroke, and the Lenoir diagram gives evidence of loss of heat, not 
gain, during a similar period. If a mass of expanding gas traces 
on the diagram the adiabatic line, then it appears as if no loss of 
heat occurred ; but as the temperature of the flame filling the 
cylinder is known to exceed 1200 C, it must be losing heat to 
the water jacket To make the expansion line keep up to the 
adiabatic a great flow of heat into the gas must be taking place, 



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TJuories of Action of Gases in Modern Gas Engine 249 

and as the only source of heat is combustion, it follows that the 
gas is burning during the expansion period. 

Dr. Slaby calculates the proportion of heat evolved by the ex- 
plosion in the Otto engine as 55 per cent., leaving 45 per cent to 
be evolved during expansion. 

This he states is due to the portion of the charge which con- 
tinues to burn after the explosion. 

The curve differs from Lenoir's in this, that while in Lenoir's 
engine all the heat is evolved at the moment of explosion, leaving 
none to be evolved during expansion, in Otto's only a part is 
evolved at first, and the reserved portion keeps up the temperature 
during expansion. 

He concludes from his experiments that the action of the 
Otto engine is truly as Mr. Otto states in his specification — 
explosion is suppressed and a slow evolution of heat is obtained, 
and this slow evolution of heat is the result of the invention and 
the cause of the economy of the engine. 

In addition to this indirect proof, experiments have been made 
at Deutz and elsewhere to show directly that stratification has a 
real existence in the Otto engine. 

An Otto engine was constructed, specially fitted with two igni- 
ting valves ; one valve was placed on the side of the cylinder at 
the end of the explosion space next the piston, so that it could 
ignite the gases at the piston ; the other valve was the usual one 
at the end of the cylinder, igniting the gases in the admission 
port 

Experiments were made to discover if the side valve would 
fire the mixture at the piston ; it was found that it did so. Con- 
secutive ignitions were obtained there. 

Diagrams were taken for comparison, with the end and the 
side valves in alternate action, care being taken to keep the charge 
in the same proportions during the trials. It was found that 
although the side valve ignited as regularly as the end valve, yet 
the diagrams were different Instead of the usual rapid ascending 
explosion line, the explosion took place more slowly, and the 
maximum pressure was not attained till late in the stroke. 

The ignitions were slower from the side valve than from the 
end valve. If an uninflammable cushion, such as Dr. Slaby so 



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250 The Gas Engine 

clearly describes, existed at the piston, one would expect that the. 
side valve would fail entirely, but it ignited quite regularly although 
more slowly than the end valve. 

This experiment is considered to prove stratification. 

To make stratification visible to the eye, a small glass model 
was constructed It consisted of a glass cylinder of about i\ ins. 
internal diameter, containing a tightly packed piston connected to 
a crank ; the stroke was about 6 ins. ; when full back, the piston 
left a considerable space to represent the explosion space. A 
brass cover was fitted to the end of the tube, and in it was bored 
a hole of about J in. diameter, representing the admission port ; 
in this hole was screwed a pet cock to which a cigarette was 
affixed 

On lighting the cigarette and then moving the piston forward 
by the crank, it was seen that the smoke of the cigarette which 
passed in did not completely fill the cylinder ; the smoke slowly 
oozed in and left a large clear space between it and the piston. 
The smoke was supposed to represent the charge of gas and air 
rushing in, and the clear air behind the piston the cushion which 
was said to exist in the Otto engine. It was supposed that in the 
glass cylinder was repeated on a small scale the action of the gases 
occurring on a larger scale in the Otto engine. In a recent papa- 
in a German engineering journal, Dr. Slaby recounts this experi- 
ment, and lays great weight upon it. He considers that it un- 
doubtedly proves the truth of the Otto theory. 

In discussion Mr. John Imray concisely states the Otto 
position as follows : 

'The change which Mr. Otto had introduced, and which 
rendered the engine a success was this : that instead of burning 
in the cylinder an explosive mixture of gas and air, he burned it 
in company with, and arranged in a certain way in respect of, a 
large volume of incombustible gas which was heated by it, and 
which diminished the speed of combustion.' 

And Mr. Bousfield states it in similar terms : 

'In the Otto gas engine the charge, varied from a charge 
which was an explosive mixture at the point of ignition to a charge 
which was merely an inert fluid near the piston. When ignition 
took place, there was an explosion close to the point of ignition 



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Theories of Action of Gases in Modern Gas Engine 251 

that was gradually communicated throughout the mass of the 
cylinder. As the ignition got further away from the primary point 
of ignition, the rate of transmission became slower, and if the 
engine were not worked too fast the ignition should gradually 
catch up the piston during its travel, all the combustible gas being 
thus consumed. When the engine was worked properly the rate 
of ignition and the speed of the engine ought to be so timed that 
the whole of the gaseous contents of the cylinder should have 
been burned out and have done their work some little time before 
the exhaust took place, so that their full effect could be seen in 
the working of the engine. This was the theory of the Otto engine.' 
From these quotations it will be seen that Mr. Otto's supporters 
agree that Mr. Otto has invented a means of suppressing explosion, 
and substituting for explosion a regulated combustion, and that 
this process is the cause of the economy of the engine. They 
are agreed that he has succeeded in preventing explosion, and 
that he does this by arranging or stratifying the charge which is 
to be used. They consider that engines previous to Mr. Otto's 
were wasteful because they used a homogeneous and therefore 
explosive charge, and that Mr. Otto's engine is economical be- 
cause it uses a heterogeneous or stratified charge, which is con- 
sequently non-explosive. 

Discussion of Mr, Otto's Theory. 

The primary fallacy of Mr. Otto's theory lies in the assumption 
that previous engines were more explosive than his, and that in 
previous engines all the heat was evolved at once : as a plain 
matter of fact this is incorrect. In the Lenoir and Hugon engines, 
as in all explosive engines, little more than one-half of the total 
heat is evolved by the explosion, and the portion reserved is evolved 
during the stroke of the engine. 

The following test of a Lenoir engine, made by the author in' 
London, very clearly shows the suppression of heat at first : 

Lenoir engine rated at one horse power. 
Cylinder 7^ inches diameter; stroke n \ inches. 
Average revolutions during test, 85 per minute. 
Gas consumed in one hour, 86 cubic feet. 



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2$2 The Gas Engine 

With full load, indicated horse power, 1-17 (average of 9 

diagrams). 
Gas consumed per indicated horse power per hour, 73-5 cubic 

feet 
Maximum temperatures of explosion, 1100 to 1200 C. 
Mixture in engine 1 vol. coal gas, 12-5 vols, of air and other 

gases. 
Heat evolved by explosion, 60 per cent, of total heat. 

The proportion of the mixture was calculated from the points of 
cut-off on the diagram, and after making allowance for the volume 
of burned gases in the clearances of the engine. It will be 
observed that only 60 per cent, of the gas is burned at first, leaving 
40 per cent to be burned during the stroke, and also that the 
temperature of the explosion never exceeds 1200 C. Now in the 
Otto engine, according to Thurston, 60 per cent, of the heat is 
evolved at explosion, and 40 afterwards, and the usual maximum 
temperature is about 1600 C. So that, so far as the slowness of 
the explosion is concerned, there is no difference, and in the in- 
tensity of the temperature produced, the Otto exceeds the Lenoir. 

It is difficult to understand how Dr. Slaby could fall into so 
obvious an error as he did, and suppose that more heat was kept 
back in the case of the Otto explosion. At the time he wrote his 
report, accounts of Hirn's, Bunsen's, and Mallard's experiments 
on explosion were in existence, all of them agreeing on the fact 
of a large suppression of heat at the maximum temperature of the 
explosion, although differing in the explanation of the fact 

Him even stated that in the Lenoir engine the pressures fell 
far short of what should be, if all the heat were evolved at once. 
Yet Dr. Slaby, in the presence of all this definite and carefully 
ascertained knowledge, is astonished when he finds only 55 per 
cent, of the total heat evolved by the explosion in the Otto engine, 
and the only explanation which occurs to him is that of stratifica- 
tion. 

If stratification exists at all in the engine, then it produces no 
measurable change in the explosion ; it neither retards the evolu- 
tion of heat, nor does it moderate the temperature. 

The explosion and expansion curves are precisely what they 
would have been with a homogeneous charge. 



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Tlieories of Action of Gases in Modern Gas Engine 253 

The mere fact that heat is suppressed in the Otto explosion 
proves nothing, because a precisely equivalent amount of heat is 
suppressed in all gaseous explosions, and Dr. Slaby's contention, 
based upon the supposed peculiarity of the Otto, falls to the 
ground. 

Dr. Slaby has been led into error by the feet that the expansion 
line of the Lenoir diagram falls below the adiabatic, while the 
expansion line of the Otto diagram remains slightly above it or 
upon it. He assumes that in the Lenoir no heat is being added 
during expansion, whereas just as much heat is being added, or 
just as much combustion is proceeding during the Lenoir stroke, 
only the cooling of the cylinder walls is greater, and the heat is 
abstracted so rapidly that the line falls below the adiabatic. This 
is due to two causes, (1) the greater proportional cooling surface 
exposed by the Lenoir engine, and (2) a longer time of exposure. 
The absence of compression and the slow piston speed makes the 
loss greater. 

Although quite as much heat is evolved during the stroke, it 
is overpowered by the greater cooling, and the line falls under the 
adiabatic. This fall is evidence of greater cooling, not of less 
evolution of heat. 

In a recent paper, 1 'Die Verbrennung in der Gasmaschine, 
Professor Schottler makes this explanation of the difference be- 
tween the lines, and states that ' Whether stratification exists or 
does not exist in the Otto engine it is unnecessary, and is not the 
cause of the slow falling of the expansion line.' In all crucial 
points the Otto theory breaks down, as proved by diagrams taken 
from his engine. 

The explosion is not suppressed ; the maximum temperatures 
produced are not lower than those previously used ; the mixture 
used is not more diluted than in the previous engines, and the in- 
tensity of the pressures, as well as the rate of their application, is 
greater. 

The mixture in the engine from Slaby's figures is 1 voL coal 
gas to 10 -5 vols, of other gases, and from Thurston's figures 1 
voL coal gas to 9*1 vols, of other gases, while Lenoir often used 
1 vol. gas to 12 of air. 

1 Zeitichrift des Vcreines dcutscher Ingenicure. Band xxx., Seite 209. 



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254 The Gas Engine 

The engine instead of using a less explosive power than the 
tenoir engine uses one more intensely explosive. 

The effect of the reduction of cooling surface and increase of 
piston velocity is to diminish the loss of heat to the cylinder walls, 
and the slowly descending line is not the cause of the economy, 
but is the effect and evidence of it 

Stratification.— -The inquiry into the existence or non-existence 
of stratification in the cylinder has no practical bearing on the 
question of economy, as the explosion curves act precisely as they 
would with homogeneous mixtures. Scientifically, however, the 
question is interesting and will be shortly considered. 

The evidence which it is considered proves its existence in the 
Otto engine is in the author's opinion most unsatisfactory. Dr. 
Slaby distinctly asserts the existence of an inert stratum next the 
piston, 'interposed between the combustible charge and the piston,' 
and Mr. Imray speaks of the 'arrangement of the charge in respect 
of a large volume of incombustible gases/ and Mr. Bousfield of 
'a charge which was merely an inert fluid next the piston/ Yet 
all the evidence in support of these positive assertions is given by 
one experiment made with an Otto engine, and one with a small 
glass model The evidence given by the experiment on the engine 
itself, in the author's opinion, disproves stratification in the Otto 
sense altogether. If the inert stratum next to the piston had any 
real existence, then the side igniting valve in the experiment made 
by Mr. Otto, should not have ignited the mixture at all. The fact 
that it did ignite regularly and consecutively, proved most dis- 
tinctly that the gas next the piston was not inert but was explosive, 
and being explosive in itself it could not act as a cushion to 
absorb heat or shock. That experiment alone settles the ques- 
tion, and proves at once the visionary nature of the cushion of 
inert gas next the piston. 

The fact that the ignitions were slower than those from the end 
slide does not get rid of the fact that ignition did take place, and 
to those who understand the sensitive nature of any igniting valve, 
it will not be difficult to comprehend how small a difference in 
adjustment will cause late and slow ignitions. At the very utmost 
the experiment points to a small difference in the dilution of the 
explosive mixture at the piston and that at the end port. 



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Theories of Action of Gases in Modern Gas Engine 255 

Experiments made by the author also prove that the mixture 
in the Otto cylinder is present in explosive proportions close up to 
the piston. The piston of a 3^ HP Otto engine was bored and 
fitted with a screw plug, which carried a small spiral of platinum 
wire in electrical connection with a battery ; the platinum spiral 
projected from the inner surface of the piston by a quarter 
of an inch. When the engine was running in the usual way, the 
wire was made incandescent by the battery and the external light 
was put out. It was proved that by a little care in getting the 
platinum to a certain temperature, the engine worked as usual, 
igniting regularly and consecutively. The spiral was made just 
hot enough to ignite when compression was complete, but not hot 
enough to ignite before compressing. If an incombustible stratum 
had existed even so close to the piston as \ in. then the wire 
should never have been able to ignite the charge at alL If the 
wire was made too hot, then ignition often took place while the 
charge was still entering, proving that no stratification existed even 
while the charge was incomplete. A little consideration of the 
arrangement of the Otto engine will show that stratification can- 
not have any existence in it The end of the combustion space is 
usually flat, and sometimes the admission port projects slightly 
into it ; the area of the admission port is about ^ of the piston 
area ; accordingly the entering gases flow into the cylinder at a 
velocity thirty times the piston velocity, or at the Otto piston 
speed, about 120 miles an hour. 

Great commotion inevitably occurs ; the entering jet projects 
itself through the gases right up against the piston, and then re- 
turns eddying and whirling till it mixes thoroughly with whatever 
may be in the cylinder. The mixture becomes practically homo- 
geneous even before compression commences. 

Experiments made by Dr. John Hopkinson and the author on 
full size glass models of the Otto cylinder show this mixing action 
very beautifully. A 3^ HP Otto cylinder was copied in every 
proportion in glass, and the valve was so arranged that it passed a 
charge of smoke at the proper time. The piston was placed at 
the end of its stroke, leaving the compression space filled with air. 
When pulled forward the valve opened to a chamber filled with 
smoke, and the smoke rushed through the port, projected right 



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256 The Gas Engine 

through the air in the space, struck the piston, and filled the 
cylinder uniformly, much faster than the eye could follow it. it 
mixed instantaneously with the air in the cylinder without evincing 
the slightest tendency to arrange itself in the manner imagined 
by Mr. Otto. Mr. Otto's experiment with a cigarette and glass 
cylinder does not, in the most remote degree, imitate the condi- 
tions occurring in his engine; the proportions are quite wrong. 
The model is much too small, and the glass cylinder is too long 
in proportion to its diameter ; then the gases are so badly throttled 
by passing through the cigarette, that when the piston is moved 
forward it leaves a partial vacuum behind it, and only a little 
smoke enters, not nearly enough to follow up the piston, but 
only sufficient to ooze into the back of the cylinder while the 
piston moves forward and expands the air which is already in the 
cylinder. It was easy for Mr. Otto to have copied his cylinder 
and valve full size and imitated precisely the conditions existing in 
his engines. 

Had he done this he would have proved complete mixing in- 
stead of stratification. Why did he refrain from doing this ? The 
question at issue is not, Can stratification be obtained by a speci- 
ally devised form of apparatus— no one doubts that it can — but, 
Does stratification exist in the Otto engine? If it does not 
exist in the Otto engine then it is perfectly plain that it cannot be 
the cause of the economy of the motor, and it is quite certain that 
it cannot exist in the Otto engine. Prof. Schottler, in the paper 
already referred to, also arrives at the conclusion that stratification 
has no existence in the Otto engine, and that Mr. Otto's small 
glass model does not truly represent the actions occurring in the 
engine. 

In all gas engines, when the charge enters the cylinder through 
a port the residual gases in the port are swept into the cylinder, 
and while the port itself is filled with gas and air mixture, free 
from admixture with residual gases, the cylinder contains the gas 
and air mixture diluted with whatever residual gases exist in 
the engine which have not been expelled by the piston. The 
mixture in the port is accordingly stronger and more inflammable 
than the mixture in the cylinder. 

In the Lenoir and Hugon engines this occurred to a marked 



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Theories of Action of Gases in Modern Gas Engine 257 

extent ; in the Hugon engine as much as 30 per cent, of the whole 
charge consisted of residual gases, and the charge in the cylinder 
was considerably more dilute than that in the admission port. In 
the Otto engine this also occurs, but it is not stratification, and it 
is not a new invention ; the cylinder is filled with explosive mix- 
ture more dilute than that in the ignition port, but still explosive 
throughout 



Causes of the Suppression of Heat at Maximum 
Temperature in Gaseous Explosions. 

Although experimenters are unanimously agreed upon the fact of 
the suppression of heat at the maximum temperatures produced by 
gaseous explosions, they differ widely in their explanation of the 
causes producing this suppression. 

Three principal theories have been proposed — 

1. Theory of Limit by Cooling. — This is Hirn's theory, and it 
assumes that when explosion occurs, a point is reached when the 
cooling effect of the enclosing walls is so great that heat is 
abstracted more rapidly than it is evolved by the explosion, and 
accordingly the temperature ceases to increase and begins to fall. 

The maximum temperature falls short of what it would do if 
no heat were lost during the progress of the explosion to the walls. 
If it be true that the cold surface of the vessel is the limiting 
cause, then the maximum pressure produced in exploding the 
same gaseous mixture, in vessels of different capacity, will greatly 
vary. When the vessel is small and the surface therefore re- 
latively large, more heat should be abstracted and lower pressure 
should be produced. This is not the case. The maximum tem- 
perature produced by an explosion is almost independent of the 
capacity of the vessel. Surface does not control maximum tem- 
perature, although increased surface increases the rapidity of the 
fall of temperature after the point of maximum temperature. 

2. Theory of Limit by Dissociation. — This is Bunsen's theory, 
and it is undoubtedly largely true. The fact that no unlimited 
temperature can be attained by combustion, even when the use of 
non-conducting materials prevents cooling almost completely, is 
so conclusively established by science and practice that gradual 

s 



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258 The Gas Engine 

combustion due to dissociation may be safely taken as occurring 
to a considerable extent at the higher temperatures used in gas 
engines. But there is a difficulty in its application to all cases. 
In experiments made with explosions in a closed vessel the 
suppression of heat is almost the same at low temperatures as at 
high temperatures ; thus with hydrogen mixtures — 

Max. temp, of explosion 900 C. ; apparent evolution of heat 55 per cent. 
i70o°C. „ „ „ 54 

If dissociation were the sole cause, then as water must dissociate 
more at the higher temperature than at the lower, the apparent 
evolution of heat should be less at 1 700 C. than at 900 C. It 
is not so. Some other cause than dissociation must therefore be 
acting to check the increase of temperature so powerfully at 
900 C. 

3. Theory of Limit by the Increasing Specific Heat of the Heated 
Gases. —Messrs. Mallard and Le Chatelier have advanced the theory 
that up to temperatures of about 1800 C. dissociation does not 
act at all or only to a trifling extent. They consider that the 
gases are completely combined or burned at the maximum 
temperature of the explosion. But the specific heat of nitrogen, 
oxygen, and the products of combustion increases with increasing 
temperature, becoming nearly doubled when approaching 2000 C 
The apparent limit is due, not to the suppression of combustion 
as required by the dissociation theory, nor to the loss of heat 
by the theory of cooling, but to the absorption of the heat which 
is completely evolved by the increasing capacity for heat of the 
ignited gases. The same objection applies to this as to the 
dissociation theory. If it were entirely true that specific heat 
increased with increasing temperature, a greater proportion of 
heat would apparently be evolved at the lower temperatures, which 
is not always the case. 

It is impossible to discriminate between the effect produced 
by increased specific heat and the effect produced by dissociation 
on the explosion curves. 

Those are the three principal theories which have been pro- 
posed, and in the author's opinion none of them completely explains 
the facts. The phenomena of explosion are very complex, and 



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Theories of Action of Gases in Modern Gas Engine 259 

no single cause explains the limit and other phenomena of 
gaseous explosion. These phenomena are more complex than 
have generally been supposed. In many chemical combina- 
tions it has been proved by Messrs. Vernon- Harcourt and 
Esson, and Dr. E. J. Mills and Dr. Gladstone, that the rate at 
which the reaction proceeds depends upon the proportions ex- 
isting between the masses of the acting substances present, and 
those neutral to the reaction, and that combination proceeds 
more slowly as dilution increases. From this it follows, that in a 
combination where no diluent is present, the first part of the 
action is more rapid than the last ; at first all the molecules in 
contact are active, but after some combination has occurred the 
product acts as a diluent. The last portion of the reaction, 
having to proceed in the presence of the greatest dilution, is 
comparatively slow. Such an action the author considers occurs 
in all gaseoui explosions, and is one of the causes preventing 
the complete evolution of all the heat present at the moment of 
the explosion. 

The subject is a difficult one, and more experiment is required 
for its complete settlement 



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2(x> The Gas Engine 



CHAPTER XL 

THE FUTURE OF THE GAS ENGINE. 

Since i860, when by the genius and perseverance of M. Lenoir 
the gas engine first emerged from the purely experimental stage, 
it has steadily and continually increased in public favour and use- 
fulness. At first more wasteful of heat than the steam engine, it 
is now more economical ; at first delicate and troublesome in the 
extreme, it is now firmly established as a convenient, safe and 
reliable motor ; at first only available for small and trifling powers, 
now really large and powerful motors are used in thousands- 
Many inventors have contributed to its progress, but its present 
position is in the main due to the patience, energy and command- 
ing ability of one man — Mr. Otto. 

In i860, the efficiency of the gas engine was only 4 per cent.; in 
1886, the efficiency of the best compression engines is 18 percent 

That is, at first a gas engine could only convert 4 out of every 
100 heat units given to it into mechanical work, as developed in 
the motor cylinder ; now it can give 18 out of every 100 units as 
indicated work. 

Having advanced in economy more than fourfold in the past 
twenty-five years, what limits exist to check its progress in the 
future ? 

Apart from the greater perfection of the mechanical arrange- 
ments of the gas engines of to-day, the great cause of improve- 
ment since i860 is the successful introduction of the compression 
principle. 

Can this principle be much further extended in its application? 
In the author's opinion, No. 

By undue increase of compression the negative work of the 
engine would be much increased, and the strains would become 



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The Future of t fie Gas Engine 261 

so great that heavier and more bulky engines would be required 
for any given power. Friction, due to this, increases more rapidly 
than efficiency ; consequently the gain in indicated efficiency 
would be more than compensated by loss of effective power. Im- 
provement must be sought elsewhere. 

The most obviously weak point of the present engine is insuffi- 
cient expansion. In the Otto engine the exhaust valve opens 
while the gases in the cylinder are still at a pressure of 30 pounds 
per square inch above atmosphere ; in the Clerk engine the 
pressure is sometimes as high as 35 pounds per square inch above 
atmosphere at the moment of exhaust. 

The gas engines discharge pressures, without utilising them, 
with which many steam engines commence. 

There is evident waste here, which can be remedied by using 
further expansion. In continuing expansion the loss of heat to 
the cylinder would not be so great as in the earlier part of the 
diagram, because the temperature is greatly reduced ; it may 
therefore be supposed, without appreciable error, that the added 
portion of the diagram would give at least as good a result when 
compared with its theoretical efficiency as the earlier part. If the 
expansion be carried so far that the pressure falls to atmosphere, 
then the theoretical efficiency of an Otto engine would be 0*5 ; 
theoretically its cycle would then be able to convert 50 per cent, 
of the heat given to it into indicated work ; practically the com- 
pression gas engine at present converts one-half of what theory 
allows ; therefore with the greater expansion it may be expected 
to give one-half of 50 per cent — that is, expansion only will raise 
the practical efficiency from 18 per cent to 25 per cent. 

By complete expansion to atmosphere, the gas consumption 
of an Otto or Clerk engine could be reduced from 20 cubic feet 
per IHP hour, to 145 cubic feet per IHP hour. There are, 
of course, practical difficulties in the way of expanding, but they 
will be overcome in time. Mr. Otto has attempted greater ex- 
pansion in various ways, and so has the author, but as yet neither 
has succeeded in carrying it beyond the experimental stage. 

It must not be supposed, as it too often is, that a high 
exhaust pressure means an uneconomical engine, or that compari- 
sons of pressure of exhaust give the smallest clues to the relative 



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262 The Gas Engine 

economy of engines. It is a very common, but a very erroneous, 
belief that if the pressure in the cylinder of a gas engine is very 
near atmospheric pressure when the exhaust valves open, that 
fact is a proof that the engine is economical. 

This is not so — indeed, it may be the very reverse. 

In engines of type 3, for example, in which, as in the Otto and 
Clerk engines, the expansion after explosion is carried to the 
initial volume existing before explosion and no further, it has 
already been shown that the actual indicated efficiency is quite 
independent of the increase of temperature above the temperature 
of compression. That is, the temperature of the explosion may 
be anything whatever above the temperature of compression with- 
out either increasing or diminishing the indicated economy. 

Suppose an Otto diagram with three expansion lines, (1) max. 
temp. 6oo° C, (2) max. temp. iooo° C, and (3) max. temp. 
1600 C, the maximum temperatures in the three cases being 
attained at the beginning of the stroke, the efficiency of these three 
lines is identical. Of course the total indicated power increases 
with increase of temperature, and diminishes with diminution of 
temperature, but the proportions of the heat given by the engine 
as work in the three cases remain constant 

The same thing applies to any number of intermediate tem- 
peratures. 

It might be supposed that the line 1 by expanding more nearly 
to atmosphere would be the more economical, and that the line 3, 
because of the high pressure of exhaust, was the more wasteful. 

It is a peculiarity of this cycle, with the expansion stated, 
that the efficiency is absolutely dependent upon compression 
alone — that is, the ratio of volume before and after expansion — and 
is quite independent of the maximum temperature. 

The case at once alters if expansion be carried to atmosphere. 
Here the line 3 would give far greater economy than the others, 
and efficiency would increase with increase of explosion tempera- 
ture. 

Suppose complete expansion successfully applied to the gas 
engine, and an actual indicated efficiency of 25 per cent, attained, 
can any further improvement be hoped for ? 

What causes the difference still existing between theory, which 



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The Future of the Gas Engine 263 

shows a possible 50 per cent., and practice, which may now realise 
25 per cent. ? 

The great loss is heat flowing from the exploded gases through 
the cylinder walls. Dr. Slaby's balance-sheet of the Otto engine 
shows — 

Per cent. 

Work indicated in c\ Under 160 

Heat lost to cylinder walls 51*0 

Heat curried away by exhaust .31*0 

Heat lost by radiation, etc. .2-0 

100 

By expanding as described it would be altered as follows : 

Percent. 

Work indicated in cylinder 25*0 

Heat lost to cylinder wall \ 51*0 

Heat carried away by exhaust .22*0 
Radiated loss, eic 20 



The work done will be increased by diminishing the loss of 
heat with the exhaust gases, but the loss of heat to the cylinder 
walls will remain constant. This assumes, of course, that the in- 
creased time of expansion is balanced in loss to cylinder walls by 
more rapid rate of fall ; if the piston velocity is not increased the 
result will not be quite so good. If, for instance, the piston 
velocity is constant, and the volume to surface ratio is constant, 
the expansion will only give results as follows : 

Work indicated in cylinder 21 x> 

Heat lost to cylinder walls and radiated . .66*5 
Heat carried away by exhaust . .12*5 

ioo'o 

Expansion so arranged as to be equivalent to the same time of 
present piston stroke, 0*2 seconds, by increasing piston velocity and 
rearranging cooling surfaces, will give 25 per cent, of total heat in 
indicated work : if surfaces and piston speed remain unaltered, so 
that the time of exposure increases in same ratio as expansion, 
then 2 1 per cent, only will be attained. With proper expansion, 
the loss of heat by the exhaust gases discharging at a high temper- 
ature may be greatly diminished, and the efficiency would be 
increased, but the change would not affect the loss of heat to 
cylinder walls ; it would even increase it 



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264 The Gas Engine 

How can this, the greatest loss in the gas engine, be reduced ? 
The loss depends, as has already been stated, upon the ratio of 
surface to volume of gases exposed to cooling, upon the time of 
exposure, and upon the elevation of the temperature of the hot 
gas above the enclosing surfaces cooling it 

It is evident that as engines increase in power, the capacity 
of cylinders of similar proportions increase as the cube of the 
diameter, while the area of the enclosing cold surfaces increases as 
the square of the diameter. As engines of greater and greater 
power are constructed, the surface exposed in proportion to volume 
becomes less and less ; the loss of heat from this cause will, there- 
fore, diminish 

Increase in piston velocity will also diminish loss, by diminishing 
time of contact : 300 feet per minute is the usual speed at present, 
and it cannot be advantageously increased in small engines, as the 
reciprocations of the parts become too frequent for durability : but 
in large engines with diminishing reciprocation, the piston speed 
may be increased to 600 feet per minute, and still be within the 
limits practised in steam engines. 

Increase in temperature of cylinder walls is also advantageous 
within certain limits. The author has found a difference of as 
much as 10 per cent upon the consumption of gas of an Otto 
engine when at 17 C, and so hot that the water in the jacket was 
just short of boiling 96 C. It is probable that still higher 
temperature could be advantageously used, but there is a limit 
imposed both by theory and practice. 

However, the cycle could be modified to permit the use of 
very hot walls, enclosing the gases at 500 C. 

When all these precautions against loss are practised in large 
engines, and the heat loss is greatly reduced, another complication 
steps in, which modifies the theory of the engine very considerably. 
That complication is the property possessed by all explosive 
gaseous mixtures of suppressing part of their heat- the phe- 
nomenon of Dissociation, the * Nachbrennen ' of the Germans, or 
the apparent change of specific heat or continued combustion of 
the French and the English. 

Although a gaseous explosion expanding in a cold cylinder 
behind a piston doing work very nearly follows the adiabatic line, 



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The Future of the Gas Engine 265 

yet if expanded under such circumstances that the loss of heat 
was greatly diminished, it would no longer do so. 

In large engines the expansion curve is always above the adia- 
batic ; in small engines it is below the adiabatic 

In fig. 53, diagram taken by Professor Thurston, if all loss of 
heat to the cylinder could have been prevented, the expanding 
line would have been an isothermal, the maximum temperature of 
1 65 7 would have been sustained to the end of the stroke, and the 
actual efficiency of the diagram would have been 0*40, that is, 
40 per cent 

At the point 7 the temperature would be 1657 , and the gases 
would still contain 60 per cent of all the heat given to them, and if 
expanded to atmosphere adiabatically, the combustion being sup- 
posed complete, then 13 per cent would be added, making a 
total efficiency of 53 per cent 

If the loss of heat through the cylinder could be totally sup- 
pressed, the possible efficiency, taking into consideration the 
properties of explosive gases is 53 per cent. It is impossible to 
completely avoid loss to the cylinder, but it will doubtless be 
greatly reduced. 

The united effect of expansion, greater piston speed and reduc- 
tion of loss of heat to the cylinder by using hot liners, when carried 
out in an engine of considerable power, would cause the attainment 
of a practical heat efficiency of at least 40 per cent, and this with- 
out any great change in the construction of gas engines now made. 
* Now, how do these efficiencies compare with those of the steam 
engine? It is generally admitted that the best steam engines 
of considerable powers and of the latest type, when in ordinary 
work do not give an efficiency greater than 10 per cent., that is, 
they do not convert more than 10 per cent of the heat given to 
the boiler in the form of fuel, into indicated work. In small engines 
of such powers as are comparable with the largest gas engines yet 
constructed, the results are not nearly so good, an efficiency of 
4 per cent being a good result. 

The reader will remember that the term efficiency, as used in 
this work throughout, is defined to mean the proportion of heat 
converted into work, to total heat given to the heat engine. 

Efficiency is often used in another sense, and considerable 



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266 Tfie Gas Engine 

confusion has arisen because of its use in different senses by diffe- 
rent writers. In comparing engines differing in their nature, the 
only standard of comparison possible is the total heat or total fuel 
given to each engine, and the proportion of total heat or total fuel 
which that engine can convert into work. The source of power is 
always combustion, and the temperature of combustion may always 
be supposed to be the superior limit of temperature whatever the 
working process, whether steam or air is the working fluid. From 
the fact of taking the total heat as the basis of comparison, the 
reader is not to infer that it is possible even in theory to convert 
all of it into work. Professor Osborne Reynolds, in a lecture be- 
fore the Institution of Civil Engineers, stated that this seemed to 
be a belief popular among engineers ; the author does not think 
that this is so. 

Certainly, the second law of Thermodynamics is not so widely 
understood among engineers as it should be, but still, few suppose 
that it is even theoretically possible to convert all the heat given 
to an engine into work. 

In the discussion on the author's paper on 'The Theory of the 
Gas Engine/ at the Institution of Civil Engineers, considerable 
confusion arose from the term efficiency being used in different 
senses by different speakers. Professor Fleeming Jenkin in his 
lecture very clearly defines the different legitimate uses of the 
term. 

Returning to the comparison of gas and steam engine heat 
efficiency, the 10 per cent, of the steam engine is probably very 
nearly as much as can be ever attained ; it may be exceeded by 
using high pressures and great expansion, but it will never be pos- 
sible to attain anything like 20 per cent. The limits of tempera- 
ture are such that if the steam cycle were perfect, only 32 percent 
of the whole heat could be converted into work ; at the boiler 
pressures and condenser temperatures used, the theoretical effi- 
ciency of the steam engine cycle is within 80 per cent, of the cycle 
of a perfect engine, that is, the efficiency theoretically possible is 
32 x o-8 = 25-6 per cent. In an experiment made by Messrs. 
B. Donkin & Co. on a 63 HP compound engine, the results as 
given by Professor Cotterill in his work on the steam engine are 
as follows : 



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The Future of the Gas Engine 267 

Per cent. 

Absolute efficiency hi 

Efficiency of a perfect engine . . . .284 
Relative efficiency 39*1 

The engine received 100 heat units from the boiler as dry 
steam, and it gave in units as indicated work in the cylinder. 
With the pressures and temperatures given, the steam engine cycle, 
if perfectly carried out, falls short of the cycle of a perfect heat 
engine between the limits, so that 227 per cent is the maximum 
efficiency which could be obtained, supposing no other loss than 
that due to the imperfection of the cycle. The cylinder losses, 
condensation, incomplete expansion and misapplication of heat, 
make the actual indicated efficiency ii'i per cent, so that half 
has gone. The furnace loss diminishes the absolute efficiency to 
9 "2 per cent, and it is extremely improbable that improvement 
can ever increase this to 18 per cent, which is the indicated 
efficiency of the gas engine as at present 

It is impossible that the steam engine can ever offer an effi- 
ciency of 40 per cent., which is quite possible with the gas engine. 

What remains to be done, then, in order to make the gas 
engine compete with steam for really large powers ? At present 
the largest gas engines do not indicate more than 40 HP, and 
very few are in use so powerful. 

The gas engine, although superior in efficiency as a heat 
engine to the steam engine, is not superior in economy except for 
small powers, where steam engines are very wasteful and the cost 
of attendance relatively great 

The unit of heat supplied in the form of coal gas is more 
costly than the unit of heat supplied in the form of coal. Gas 
producers are required which will convert the whole of the fuel 
into gas as readily as steam is produced, and with no greater loss 
of heat than a boiler has. 

Mr. J. E. Dowson's producer is the only one at present in 
existence giving suitable gas, and it requires the special fuel 
anthracite. 

The use of ordinary fuel has not yet succeeded. 

A good gas producer, giving gas usable and free from tar, is 
much wanted. 



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268 The Gas Engine 

But when all this is done, the gas engine remains in some 
respects inferior to the steam engine. It would then be a great 
advance in economy, as it is at present much superior as a heat 
engine, or machine for the conversion of heat into work. But 
mechanically it would still be inferior to steam. 

As a piece of mechanism, the steam engine is almost perfect ; 
it is started, stopped, and regulated in a very perfect manner. Its 
motion is, in good examples, almost perfectly uniform under 
variation of load, and but little fly-wheel power is required, be- 
cause there is little or no negative work. 

Its motion is perfectly under control. 

The gas engine itself requires much improvement in this re- 
spect ; it is a comparatively inferior machine ; at best it receives 
only one impulse every revolution when at full power, and when 
under light loads only an occasional impulse. 

Means must be found to make it double acting, and to 
diminish the power of the impulses instead of diminishing their 
frequency for governing. 

Means must also be found to start and stop as in steam 
engines ; the present starting gear is a step in this direction, but 
requires development 

All this can and will be done; it is a matter of time and 
patience. It can and will be made as mechanically perfect and 
controllable as the steam engine. Flame and explosion, seemingly 
so untameable and destructive, have been to a great extent tamed 
and harnessed in present engines. Experience is growing, by 
which it will be as easily and certainly directed in the cylinder of 
an engine as steam is at present. The furnace, at present sepa- 
rated from the engine, will be transferred to the engine itself, and 
the power required will be generated as required for each stroke, 
and the system of storing it up in enormous reservoirs — steam 
boilers — finally abandoned. 

The masses of smoke polluting our atmosphere will be entirely 
abolished so far as motive power is concerned. 

The author cannot do better in conclusion than quote the 
late Professor Fleeming Jenkin, expressing his belief in the future 
of this form of motor. 

' Since that is the case now, and since theory shows that it is 



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The Future of the Gas Engine 269 

possible to increase the efficiency of the actual gas engine two or 
even threefold, then the conclusion seems irresistible, that gas 
engines will ultimately supplant the steam engine. The steam 
engine has been improved nearly as far as possible, but the 
internal-combustion gas engine can undoubtedly be greatly im- 
proved, and must command a brilliant future. I feel it a very 
great privilege to have been allowed to say this to you, and I say 
it with the strongest personal conviction/ 



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271 



PART II. 

GAS ENGINES PRODUCED SINCE 1886. 
CHAPTER I. 

GAS ENGINES GIVING AN IMPULSE FOR EVERY REVOLUTION. 

The first part of this work was published in 1886, and the 
account of the different engines described is accurate up to that 
date ; the scientific part of the work, dealing with the thermo- 
dynamics of the gas engine, and the various causes of loss 
operating in working engines, is as true to-day as when written, 
and requires no modification. 

The ten years elapsing between 1886 and the present year 
have however, seen many important changes in details of con 
struction, and a considerable advance has been made in the 
construction of large gas engines. Gas producers have been 
more extensively adopted; petroleum engines have been pro- 
duced which are practically useful although not quite so well 
understood as gas engines ] very effective and simple starting 
gears have been invented and extensively applied ; the slide 
valve igniters have been practically abandoned, and the hot tube 
igniters have taken their place ; the compound principle has 
been advanced a stage ; and generally the gas engine has been 
made as reliable in its action as any steam engine. 

The Otto patent of 1876 (No. 2081) expired in 1890, and 
this event has had a most important effect on the gas engine 
from a commercial point of view ; so many engineers now make 
Otto cycle engines that the selling price for any given power 
has fallen from 40 per cent, to 50 per cent, as compared with 
1886 prices. So far this fall in prices has had one good effect, 



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272 The Gas Engine 

and has greatly increased the number of gas engines in use, by 
bringing the cost within the means of many small manufacturers 
formerly unable to stand the considerable first cost of a gas 
engine. 

The lapse of the Otto master patent has, however, had 
another effect which may prove an obstacle in the development 
of the gas engine. In Britain the Otto cycle engine is now 
practically the only engine manufactured ; the whole of the 
impulse-every-revolution engines have disappeared from the 
market ; many are still in successful work, but their makers 
with wonderful unanimity have ceased their manufacture, and 
have generally taken to the construction of Otto engines. At 
the present time practically the whole of the engines manufactured 
and offered for sale in this country by engineers are engines 
operating on the Otto cycle, giving one impulse for every four 
single strokes of the piston. 

This state of affairs offers emphatic testimony to the practical 
advantages of the Otto cycle, and in the author's opinion engi- 
neers are correct in considering the Otto cycle as likely to remain 
unrivalled for small and perhaps moderate power gas engines. 
For really large engines, however, it appears to him that the 
Otto cycle is inherently defective, and he still considers impulse 
every revolution or two impulses per revolution as much prefer- 
able, and as certain to prove the type of the future for really large 
power engines. It is therefore much to be regretted that for the 
present engineers have practically ceased their efforts in the 
direction of more frequent impulses, and have devoted them- 
selves entirely to the development of the Otto type. 

The following are the leading makers of Otto cycle gas 
engines in Britain : 

Messrs. Crossley Bros., Limited, Manchester ; Messrs. J. E. H. 
Andrew & Co., Limited, Reddish ; Messrs. T. B. Barker & Co., 
Birmingham ; Messrs. Tangyes, Limited, Birmingham ; Messrs. 
Dick, Kerr & Co., Limited, Kilmarnock ; Messrs. Robey & Co., 
Limited, Lincoln ; Messrs. Fielding & Piatt, Gloucester ; and 
Messrs. P. Burt & Co., Glasgow. 

There are many other engineers who manufacture good Otto 
cycle engines, but a description of engines by several of these 



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Gas Engines giving an Impulse for Every Revolution 273 

makers will put the reader in full possession of the leading points 
of recent gas-engine practice. Before beginning the Otto cycle 
engines, however, it is advisable to consider shortly the position 
of impulse-every-revolution engines from 1886. 

Atkinson's * Cycle * Gas Engine. — The most important of the 
engines giving an impulse every revolution produced since the 
year 1886, was undoubtedly the engine called by Mr. Atkinson 
the ' Cycle.' At page 197 of this work will be found a description 
of Atkinson's Differential Gas Engine, in which a most ingenious 
attempt was made to obtain greater expansion than was given in 
Otto engines. To a certain extent this attempt was successful, 
and the combustible mixture was expanded after explosion to a 
volume considerably greater than the volume existing before 
compression. Considerable economy was obtained in the engine, 
but certain practical difficulties intervened which caused Mr. 
Atkinson to invent another engine quite as ingenious, but 
having one piston instead of two. 

The engine is shown in longitudinal section at fig. 102, in plan 
at fig. 103, and at fig. 104 at 1, 2, 3 and 4 are given the four 
principal positions of the linkage and piston, carrying into effect 
the operations of the engine. The piston makes two out and two 
in strokes for every explosion given, and in this feature the engine 
resembles the Otto, but here the resemblance ends. The piston 
is so coupled to the crank shaft that the whole four single strokes 
are performed during one revolution ; and, moreover, the four 
strokes differ in length and range in the cylinder, so that while 
on one in-stroke the piston proceeds almost entirely to the end of 
the cylinder to sweep out practically the whole of the products of 
combustion, on the next in-stroke it stops short and leaves a con- 
siderable compression space ; on one out-stroke also a short 
distance is traversed, and on the other out-stroke a longer stroke 
is made to obtain greater expansion. That is, during the exhaust- 
ing in-stroke the piston moves close up to the cylinder cover ; 
during the compressing in-stroke it leaves a considerable space ; 
during the expanding out- stroke after explosion the piston makes 
its longest sweep ; and during the charging out-stroke it makes a 
shorter sweep. 

T 



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274 



Tfu Gas Engine 




Fig. 102. — Atkinson Cycle Engine (longitudinal section). 




Fig. 103. — Atkinson Cycle Engine (plan). 



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Gas Engines giving an Impulse for Every Revolution 275 

By these variations in length of stroke and position of sweep 
in the cylinder, the piston not only sweeps out the whole of the 
products of combustion, but it also expands the burned gases 
beyond the volume existing before compression. The linkage 
invented by Mr. Atkinson to perform these operations is ex- 
tremely simple and ingenious, and will be best followed by an 
examination of the diagrammatic illustration 1, 2, 3 and 4 of 

fig- 104- 

The cylinder a contains the piston b, which piston is con- 
nected to the crank c, which rotates in the direction of the arrow 
5 ; the connecting rod d from the crank c connects to a toggle 
lever e, pivoting from the fixed centre 6, at the centre 7 ; the 
connecting rod d carries a short lever d 1 rigidly attached to it 
and carrying a pin or centre 8, and to this pin or centre 8 is con- 
nected the second connecting rod or toggle link f. By the 
rotation of the crank c, the toggle lever e is constrained to 
oscillate on its pivoting point or centre 6, between the limits 
shown by the dotted lines 9 and 10. The centre 7 of the con- 
necting rod d and lever e thus describes the arc shown by the 
dotted line between the lines 9 and 10, and if the rod f were con- 
nected to the centre 7 the piston b would make two out and two 
in-strokes for every revolution of the crank c, and the two strokes 
would be of equal or unequal length depending on the equal or 
unequal oscillation of the toggle lever e about a central position 
with regard to the connecting rod f, but in this case the in-stroke 
of the piston b would always terminate at the same point, and so 
one stroke could not be arranged to clear out the exhaust gases, 
while another left the required compression space. To produce 
this desired variation, Mr. Atkinson provides the short lever d 1 
which oscillates about the centre 7, describing an arc between the 
dotted lines n and 12 about the centre line of the lever e. The 
position of the centre 8 relative to the centre line of e depends on the 
position of the crank c in the crank circle, and the angle between 
the lines n and 12 depends upon the relative length of the con- 
necting rod d, as compared with the diameter of the circle 
described by the crank c, and also the angle between the lines 9 
and 10. 

In diagram 1 (fig. 104) the piston b is at its extreme in 



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276 



The Gas Engine 



Dujgr&m I 



! ; \ 




Fig. 104. — Atkinson Cycle Engine 
(four positions of linkage). 



position, and all products 
of combustion have been 
expelled; the crank c ro- 
tates in the direction of the 
arrow 5, and in diagram 2 
the piston b has made its 
out charging stroke, taking 
into the cylinder a charge 
of gas and air at atmospheric 
pressure. It is to be ob- 
served that in diagram 2 
the piston b, although at 
the end of its charging 
stroke, still remains within 
the cylinder a ; in diagram 
3 the crank c has still 
further rotated, and now 
the piston b has attained 
the extreme in-end of its 
compression stroke, the 
mixed gases are fully com- 
pressed and ready for ex- 
plosion, the explosion takes 
place at the position shown 
in diagram 3, and the crank 
c continuing to rotate, the 
parts at the extreme out- 
ward position of the piston 
b after expanding the gases 
assume the position of dia- 
gram 4. In this latter 
position it will be observed 
that the piston b has tra- 
velled somewhat out of the 
cylinder a, that is it has 
made a longer stroke than 
the compression stroke. 
The stroke made in passing 



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Gas Engines giving an Impulse for Every Revolution 277 

from the position of diagram 4 to that of diagram 1 is the longest 
of all strokes, as in it the piston passes from the extreme out- 
position of expansion right into the cylinder cover, and sweeps 
out all the products of combustion. The next out-stroke is 
shorter, taking in the charge ; the following in-stroke is shorter 
still, compressing the charge and leaving a compression space ; 
then follows the longest out-stroke, that of expanding the gases 
after explosion. A comparison of diagrams 1 and 3 shows the 
reason of the difference of position of the piston b ; although in 
both cases the toggle lever e is in practically the same position, 
in 1 the crank c is on one side of the crank circle, while in 2 it is 
on the other side, so that the lever d is thrown from the top of 
the centre line of the toggle lever e to a position under it, but the 
effect of the movement is to draw the piston forward from the 
cylinder cover. By studying the positions of the lever d and the 
positions of the toggle lever e from the diagrams, the action will 
be readily followed. 

In the engine rated at 6 HP nominal, the cylinder is 95 ins. 
diameter, and the four successive strokes are as follows : 

1st (out-stroke) Suction of gas and air charge . 6*33 ins. 

2nd (in-stroke) Compression of charge . . . 5*03 ins. 

3rd (out-stroke) Working expansion after explosion 11*13 ins. 

4th (in-stroke) Discharging exhaust . . . 12*43 ins. 

The construction of the 6 HP engine is shown at figs. 102 and 
103 in longitudinal section and elevation ; a is the cylinder ; b 
the piston ; c the crank ; d the connecting rod to the toggle lever ; 
e the toggle lever ; d ! the short connecting rod lever ; f the con- 
necting rod between the piston and the pin 8 on the lever d 1 ; g is 
the water jacket surrounding the cylinder and fitted with the usual 
openings for pipe connections to the tank ; h is an incandescent 
igniting tube, open to the cylinder, and arranged to operate with- 
out timing valve in a manner to be described later on ; 1 is the 
exhaust valve ; and k the gas and air inlet valve (shown in plan, 
fig. 103) ; l is the gas valve. All three valves are of the usual 
conical -seated lift type held on their seats by springs, and they are 
operated from the crank shaft by cams i 1 k 1 , and rods i 2 k 2 , in 
the usual way. The governor is indicated at l 1 , and it is of the 
rotating centrifugal type ; it acts on a rod connecting between the 



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278 T/ie Gas Engine 

actuating cam and the gas valve stem to cause the end of the rod to 
be withdrawn, and the gas valve stem missed, so leaving the gas 
valve closed for a stroke or a number of strokes. This also is a 
common device. 

Diagrams and Gas Consumption, — A test of the first ' Cycle ' 
engine constructed was made in April 1887 by Professor W. C. 
Unwin, F.R.S., for the British Gas Engine Co., Ltd., the makers 
of the engine in London. 

The engine was rated at 4 HP nominal, the diameter of the 
cylinder 7*5 ins. and the expansion or working stroke 9/25 ins. 

The leading results obtained were as follows : 

Indicated Horse Power . . . . 5*563 

Brake ,, 4-889 

Gas consumed in one hour 100 cb. ft 

Gas consumption per I HP per hour . . 1978 cb. ft. 

Gas consumption per brake HP per hour . . 22*50 cb. ft. 

Efficiency of mechanism 87*9 per cent. 

Heating value of gas in lbs. degree C° per cb. ft. . 349*3 

Professor Unwin accounts for every 100 heat units used by 
the engine as follows : 

Accounted for in indicator diagram .... 20*62 

Given to jacket water 19 "37 

Difference, exhaust gases, radiation, &c. . 6o*z 



An indicator diagram taken during the test is given at fig. 105, 
and in dotted lines on the same diagram is one taken by Dr. Slaby 
from a 4 HP Otto engine. This latter diagram was taken by 
Dr. Slaby during a test referred to at page 1 70 of this work. 

The ratio of the expansion in the Otto engine was 27 as com- 
pared with 375 in Atkinson's ; that is, in the Otto engine, the 
volume of the compression space being taken as 1, then the total 
volume behind the piston, when the piston was full out, was 
77 volumes ; the sweep of the piston was therefore 17 times the 
volume of the compression space ; in the Atkinson engine, the 
volume of the compression space being 1, the volume swept by 



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Gas Engines giving an Impulse for Every Revolution 279 

the piston during expansion was 275 ; the gases contained in 
the compression space were thus expanded from 1 volume to 
375 volumes. In the author's opinion, Professor Unwind 
diagram fig. 105 is hardly fair to the Otto engine, as it appears 
to somewhat exaggerate the amount of expansion obtained in the 
cycle engine as compared with the Otto, and the diagram should 
be so corrected as to allow for the differing combustion spaces. 
The expansion, however, in the Atkinson engine is doubtless much 
greater than in the Otto, and accordingly the gases fall to a 



t 



m 



L 




^tnvLjf|« 



. ^r»J-\J^t.KJ*TS-U^ r *» 



Fig. 105.— Atkinson Cycle Engine (Prof. Unwin's diagram). 

pressure of about 15 lbs. per square inch before the exhaust valve 
is opened. 

An important series of tests were made by judges appointed 
by the Society of Arts, Dr. John Hopkinson, F.R.S., Professor 
A. B. W. Kennedy, F.R.S., and Mr. Beauchamp Tower, at South 
Kensington in 1888, of the Crossley, Griffin, and * Cycle' gas 
engines, from which it appeared that the Atkinson ' Cycle ' gave 
distinctly the lowest gas consumption. The principal results 
obtained were as follows : 



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280 TIte Gas Engine 

Society of Arts Trial.— Atkinson Engine. 

Indicated Horse Power n'15 

Brake 9*48 

Gas consumed in cylinder in one hour . . 209*8 cb. ft. 
Gas consumed for ignition in one hour . 4*5 cb. ft 

Gas consumption per I HP per hour total . . 19*22 cb. ft. 

Gas consumption per brake HP per hour total . 22*61 cb. ft. 

Efficiency of mechanism 85 per cent. 

Heating value of gas in lb. degree C, per cb. ft. 351*6 

Revolutions per minute , 131 *i 

Explosions per minute ..... 121 *6 

Mean initial pressure, above atmospheric . . 166 lbs. per sq. in. 

Mean effective pressure 46*07 lbs. per sq. in. 

Cooling water per hour 680 lbs. 

Rise of temperature cooling water . . . 50 F. 

The engine was rated at 6 HP nominal ; the cylinder was 
9*5 inches diameter ; suction stroke 6*33 inches ; compression 
stroke 5*03 inches ; working or expansion stroke 11*13 inches; 
and exhaust stroke 12*43 inches. 

The test giving these figures was of 6 hours' duration, and 
the engine was continually loaded to full power ; indicator dia- 
grams were taken every 15 minutes, and diagrams were also 

taken with light springs to find 

«Tm* Pnuur* f6/j the power absorbed in the pump- 
Revotuhoa* ptr mm I3Q5Q r , , .it- 

explosion* * . izo 7 1 mg and exhausting strokes. Fig. 

106 is a diagram taken during 

this trial, and the leading par- 

_ ticulars are marked upon it. 

" Jct/ty»#. Fig. 107 shows an ideal dia- 

Fig. 106.— Atkinson Cycle Engine &™> m superposed upon an actual 

(Society of Arts diagram). diagram; the ideal diagram is 

the one assumed by the judges in 
the Society of Arts trial as fairly corresponding with the actual 
conditions, lines have been straightened out, and curves made 
to follow a different law in order to obtain approximately correct 
figures for temperatures and heat volumes. Standard points 
a, b, c, d, e, f, and g have been taken, and the volumes 
existing behind the piston accurately measured at the various 
points. The point a, for example, represents the farthest in 
point when the piston is full back, discharging the products of 




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Gas Engines giving an Impulse for Every Revolution 281 



combustion. The piston moves out from a to b, taking in the 
charge of gas and air ; the piston then returns from b to c, com- 
pressing the charge to the pressure and volume indicated. The 
explosion then occurs, and during the rise of pressure and tem- 
perature the piston is supposed to be stationary, that is the volume 
behind the piston is the same when the pressure attains its 
maximum as indicated at d as at the point c, so that the heat 
added by the explosion is added when the gases are at constant 
volume ; from d to e the 
piston is supposed to move 
out while the pressure remains 
constant, that is the heat added 
from d to e is added at con- 
stant pressure. The hot gases 
are supposed to expand from 
e to f, following truly a de- 
finite curve in which p v n = 
constant. In the diagram n 
is taken as 1264, and the 
curve e f has the equation 
p v v*&\ — constant. 

The value of n for the 
compression curve is 1*205, 
and assuming the specific heat 
of the charge the same as that 
of air, which assumption is 
very nearly true, then the value 
of n should be 1*408 ; the 
curve of compression in this 
diagram is therefore below the adiabatic, and the charge is losing 
heat to the sides of the cylinder during compression. 

The value of n for the expansion line e f is 1 '264, which proves 
the curve to be much flatter than would have been given by the 
adiabatic expansion of a volume of air heated to the maximum 
temperature at e. The ratio of the specific heats of the expand- 
ing charge at constant pressure and constant volume has been 
calculated by the judges as 1*376 on the assumption of the pre- 
sence in the charge of the products of complete combustion. 




Atkinson Ensinc 



** tfrcfrn 



Fig. 107. — Atkinson Cycle Engine 
(Society of Arts actual and ideal 
diagram). 



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282 



The Gas Engine 



This in the author's opinion is a quite erroneous assumption, as 
only about one-half of the total heat of the gas present is accounted 
for by the maximum temperature, so that the specific heat could 
not change to the extent assumed ; the value of «, however, for 
the expanding charge is somewhere between 1*376 and 1*408, so 
that the error introduced is not great. 

The following table gives the pressure, volumes, and tem- 
perature at the various points of the ideal diagram, fig. 107 : 



Pressure, 
lbs. persq. in. absolute 


Volume 
in cub. feet 


Temperature, 
degrees C 


A 1487 
B 1487 
C 50*30 
D 180*90 


o*o54 

o*324 
0118 
0118 


46 *6 C. 

126*4 c. 
1182*5 c. 


E 18090 


OI35 


1388 1 c. 


F 29*00 
G 1487 


OS75 
o'575 


849*2 c 
849*2 c. 



The report gives full calculations of heating value of the gas 
used, specific heat of products of combustion, and many other 
details ; several of these matters will be more fully discussed later 
on, in comparing the results obtained from different engines. 

It is desirable to note here, however, that the ratio of air to 
gas entering the cylinder is calculated as 1 volume gas to 
9-33 volumes of air. It is unfortunate that the ratio was not 
determined by independent measurement of both gas and air by 
separate meters, as was done in Professor R. H. Thurston's 
American test, described on page 175 of this work. Comparing 
the proportions of coal gas and air plus other gases present, it 
is interesting to note that in Thurston's experiments the entering 
charge contained 1 volume of gas to 7 volumes of air, but when 
mixed with the products of combustion in the compression space 
the average composition was 1 volume coal gas to 9*1 volumes of 
other gases. The composition of the mixture in the two cases 
thus appears to be practically the same. In the Otto engine, 
however, the temperature of the charge was much higher before 
compression than in the Atkinson engine, as was also the tern- 



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Gas Engines giving an Impulse for Every Revolution 283 

perature of compression ; the maximum temperature of the ex- 
plosion would appear to be higher in consequence. 

The report gives the heat account of the foregoing test as 
follows : 

Per cent. 
Heat turned into work as shown by indicator diagrams . . 22*8 

Heat rejected in jacket water 27*0 

Heat rejected in exhaust, lost by imperfect combustion, and 

otherwise unaccounted for 50*2 



This gas consumption of 19*22 cub. ft. per IHP per hour, 
giving an efficiency of 22-8 per cent, was the best result so far as 
economy was concerned up to the date of the trial, September 
1888. 

General Remarks. — The Atkinson ' Cycle ' engine was manu- 
factured and sold by the British Gas Engine Company, London, 
from 1887 to the beginning of 1893, and during that period the 
author is informed that somewhat over 1,000 gas engines were 
sold ; the engine, however, notwithstanding the great ingenuity 
of its construction and its unrivalled economy of gas consump- 
tion, never became really popular. Difficulties were experienced 
with the linkage, which had at least five working pins as compared 
with the two pins of the ordinary connecting rod, and these diffi- 
culties ultimately led the inventor to return to an engine of less 
uncommon construction, having only the ordinary crank and 
connecting rod. 

Mr. Atkinson, however, in his ' Cycle ' engine proved absolutely 
the possibility of obtaining great economy in gas consumption by 
expanding the gases after explosion to a volume much greater 
than existed before compression. By his ingenious linkage he 
caused one piston to perform four strokes within one revolution 
of the crank shaft ; he also proved conclusively a point for which 
the present author has long contended — namely, that better 
results are to be obtained in a gas engine by expelling the whole 
of the products of combustion from the cylinder than by retaining 
them. 

The c Cycle ' engine has a very high piston speed for a given 
number of revolutions of the crank shaft, as each complete stroke 



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284 The Gas Engine 

of the piston was accomplished in about one- quarter revolution, 
as will be clearly seen by inspecting the diagram, fig. 104. This 
high piston speed, although advantageous so far as gas consump- 
tion was concerned, must have been detrimental to the smooth 
and long-continued satisfactory working of the engine, as the 
movements of the piston rods and links were of a kind which 
could not be conveniently balanced. 

The engine was made in sizes up to about 30 HP brake, and 
the author understands that one 100 HP engine was constructed, 
but he is informed that this size was never placed on the market 

Atkinson's ' Utiliti ' Gas Engine. — This engine was invented 
by Mr. Atkinson with the object of retaining all the economy of 
the ' Cycle ' gas engine, while returning to the ordinary mechanical 
arrangement of piston, crank, and connecting rod, which has had 
the sanction of engineers and the public, inasmuch as it is prac- 
tically the only construction adopted in steam engines. 

The linkage of the c Cycle ' engine, although most admirable 
from an experimental point of view, was not such as an engineer 
would care to adopt in a high-speed or even a high-power engine, 
and although it served its purpose by proving to demonstration 
many interesting points, yet the present author was much pleased 
to see Mr. Atkinson depart from it. 

The ' Utility ' engine never attained any real commercial im- 
portance, as the British Gas Engine Company gave up business 
shortly after they had begun its manufacture. The Otto cycle 
had just then taken so firm a hold upon the public, that it 
appeared useless to sue for popular favour with any impulse-every- 
revolution engine, however good. 

The engine is of the greatest interest to engineers, however, as 
it proves how great economy can be obtained with an impulse- 
every-revolution engine. 

The ' Utility ' engine resembles in many points the Clerk and 
Robson engines. One side of the piston operates as a pump and 
pumps air into a chamber at low pressure, from which it flows 
through a valve into the power side of the cylinder, and displaces 
the exhaust gases before it through a port or ports uncovered by 
the forward movement of the piston . The cylinder thus contains 



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Gas Engines giving an Impulse for Every Revolution 285 

a quantity of air, which is compressed by the piston on its return 
stroke, and charged during compression with a charge of gas and 
air mixture, the gas, however, in the mixture being present in 
proportion too great to be explosive. 

The trunk piston operates in the cylinder connected to the 
crank shaft by the connecting rod. The whole front of the 
cylinder and the rod and crank shaft are inclosed within a casing, 
and a back cover is arranged to contain the compression or ex- 
plosion space. A chamber or casing connects by a pipe with 
an automatic inlet valve, and another automatic inlet valve admits 
air to the casing or chamber. A pump is operated by an eccentric 
on the crank shaft, and it takes in a charge of gas and air by way 
of a valve and the gas cock, and discharges the charge at the 
proper time by way of the valve. The piston overruns the exhaust 
port at about half-forward stroke, and the port is controlled by a 
piston valve, so that, although the piston uncovers the exhaust 
port at mid-stroke, yet the exhaust gases are not discharged to 
the atmosphere till the exhaust valve is opened at the termination 
of the out-stroke. 

The action of the engine is as follows : On the in-stroke the 
piston draws into the chamber a charge of pure air by way of the air 
valve, and on the out-stroke it compresses this charge to a pressure 
of about 5 lbs. per square inch. When the piston is full forward, 
then the exhaust valve is opened, and the pressure within the 
working cylinder falls to atmosphere and the pressure in the 
chamber lifts the charge valve, and air rushes by way of a pipe 
through the charge valve and enters the cylinder, clearing before 
it the exhaust gases through the exhaust port and valve, which is 
then open. The piston then returns, discharging the rest of the 
exhaust gases through the port until the piston crosses that port, 
when it begins to compress the air charge. Just as the port is 
closed, the gas and air pump begins to discharge its contents, a 
mixture of air and gas, into the combustion space of the cylinder 
by way of the gas and air valve. The gas and air mixture in the 
pump has too little air to make the charge explosive, and so it is 
impossible for the mixture to ignite in the pump. The gas being 
already mixed with air only requires the addition of a further 
quantity to become explosive, so that by the time the charge is 



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286 The Gas Engine 

compressed the gas is almost uniformly mixed with the air, and 
is in a state to produce a powerful explosion. The mixture 
is expanded by this arrangement to a volume after explosion 
and expansion much greater than the volume existing before 
compression, and so considerable advantage is obtained in 
economy. 

The cycle of operation of this engine is very similar to that of 
previous engines, but Mr. Atkinson, by his thorough knowledge 
of gas engine detail, has obtained results, he informed the author, 
which have surpassed those previously obtained with the cycle 
engine. The author regrets that he has been unable to obtain 
authenticated tests and diagrams of this engine. 

Other Impulse- Every -Revolution Engines. — The other impulse- 
every-revolution engines which have appeared since 1886 are : 
The Campbell Gas Engine, manufactured by the Campbell Gas 
Engine Co., Engineers, Halifax ; the Midland Gas Engine, 
made by Messrs. John Taylor & Co., Nottingham ; the Trent 
Gas Engine, manufactured by the Trent Gas Engine Co., 
Nottingham ; the Day Gas Engine, constructed by Messrs. 
Day & Co., of Bath ; and the Fawcett Engine, constructed by 
Messrs. Fawcett, Preston & Co., Liverpool. 

The * Campbell Gas Engine ' follows the cycle of operations 
first adopted by Clerk, and described at page 184 of this work. 
It has two cylinders, respectively pump and motor, driven from 
cranks placed at almost right angles to each other, the pump 
crank leading. The pump takes in a charge of gas and air, and 
the motor piston overruns a port in the side of the cylinder at 
the out-end of its stroke to discharge the exhaust gases. When 
the pressure in the motor cylinder has fallen to atmosphere, the 
pump forces its charge into the back cover of the motor cylinder 
through a check valve, displacing before it the products of com- 
bustion through an exhaust port ; the motor piston then returns, 
compressing the contents of the cylinder into the compression 
space. The charge is then fired and the piston performs its 
working stroke. This is the Clerk cycle. 

The Campbell engine, however, differs in detail from the 
Clerk engine to some extent. 



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Gas Engines giving an Impulse for Every Revolution 287 

A hot tube igniter is used, and a vibrating pendulum governor 
has been applied. 

The Midland Gas Engine also operates on the Clerk cycle. 
An ignition tube is used, and governing is performed by centri- 
fugal governor. 

The Trent Gas Engine is the invention of Mr. Richard Simon 
of Nottingham, and in it a trunk piston of two diameters is 
caused to perform the combined operations of working and 
pump pistons. Fig. no is a vertical section through the com- 
bustion or compression space, which in this engine is separate 
from the cylinder proper. 



WM//////S//S/ZV%M 



%>WV/S///J/S7777Z%%& 




Fig. 108.— Trent Gas Engine (vertical section of cylinder). 

Fig. 108 is a vertical section through the cylinder ; fig. 109 is 
a horizontal section also through the cylinder, showing cylinder 
and combustion space with the piston removed ; and fig. no is a 
vertical section through the combustion space. The cylinder 
has two diameters a and c, and in it fits a trunk piston b d ; 
the smaller diameter b forms the motor or working piston, and 
the larger diameter d forms the pump piston ; the pump cylinder 
being formed by the annulus around the trunk piston b. Both 
pistons b and d are thus operated together from a crank shaft by 
means of one connecting rod. m is the explosion chamber, and 
there are three main valves \ e the inlet valve to the pump ; o the 



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288 



The Gas Engine 



discharge valve from the pump to the compression space m ; and 
r the exhaust valve, s is the timing valve opening to the hot 



^y^mmmmmmmiW 



wmBB&it88&B23Et Wtmtazmmaxmsaaanatm 




H A 



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:;-:a » v . i ■ ■ ■ . — w . ■■■ ■ ■ . ■*■ . ,■ „ 



2222S2SSI 






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Fig. 109. — Trent Gas Engine (horizontal section of cylinder). 










f 





1 — i 



2 



Fig. no. — Trent Gas Engine (vertical section through combustion space). 

tube. When the piston b d makes its out-stroke, gas and air 
mixture is drawn into the annular space surrounding the trunk 



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Gas Engines giving an Impulse for Every Revolution 289 

piston b through the charge inlet valve e. On the in-stroke (the 
valve being closed mechanically) the mixture of gas and air is 
forced from the pump cylinder through the valve o, also operated 
mechanically into the combustion chamber m, and partly into the 
cylinder a, where it assists to displace the exhaust gases from the 
cylinder through the exhaust valve r. The horizontal rib or par- 
tition h prevents the direct flow of the entering charge to the 
exhaust valve r. At a certain point of the return stroke, so 
arranged as to prevent or minimise loss of charge by way of the 
exhaust valve r with the exhaust gases, the exhaust valve is closed 
and the pump piston continues to force mixture into the space m 
while the piston B compresses the charge in the cylinder ; both 
pistons b d thus compress the charge, and at the in-end of the 
stroke, just after the valve o has been closed, the valve s is 
opened and the compressed charge is fired. The piston is forced 
out under the resulting pressure ; the return stroke is performed 
by the energy of the fly wheel. 

Diagrams and Gas Consumption.— From tests published by 
the Trent Gas Engine Co. as made by Mr. F. L. Guilford, of 
Messrs. G. R. Cowen & Co., Engineers, Nottingham, it appears 




Fig. hi. — Trent Gas Engine (diagram from power cylinder). 

that an engine rated at 4 HP nominal gave 10-2 IHP at 174 
revolutions, but the brake HP was only 6*4 horse. The gas 
consumption was 180 ft. per hour. 

The enormous difference between the brake power and the 
indicated appears to the author to point to an omission on the 
part of the experimenter ; the mechanical efficiency could not 
have been so low as 63 per cent. ; the pump diagram cannot have 
been deducted from the motor diagram, 

U 



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2go The Gas Engine 

Fig. in is a diagram taken from the power cylinder of a 
4 HP engine : it shows a compression pressure of 36 lbs. per 
square inch above atmosphere, with a maximum pressure after 
ignition of only 84 lbs. above atmosphere. The gases are ex- 
panded down to about 15 lbs. per square inch before discharge. 
This diagram proves conclusively that a large proportion of 
exhaust gases remained in the engine cylinder unexpelled. The 
rapidity of the ignition also shows that the combustion space M 
was filled with rich mixture. 

The average available pressure cannot be obtained from this 
diagram in the absence of the pump diagram. 

General Remarks. — This type of engine has very grave dis- 
advantages, low average available pressure, large cooling surfaces, 
large volumes of exhaust products remaining in the charge, and 
consequent liability to back ignition if any attempt is made to use 
high compression ; from these difficulties it follows that no great 
economy in gas consumption can be obtained. 

The engine was manufactured for some years, but in 1894 the 
Company ceased business, and the engine does not now appear to 
be manufactured. 

The Day Gas Engine. — This engine uses the same cycle of 
operations for charging the working cylinder as was adopted in 
the Tangye-Robson gas engine, and also in the Stockport engine, 
described in pages 195 and 197 of this work, but the inventor in- 
geniously dispenses with all valves and valve gear such as cams or 
eccentrics. 

The engine in one form may be described as valveless, and its 
only moving parts are, piston, connecting rod and crank shaft ; 
there is absolutely no valve used except a governor valve. Fig. 
112 is a sectional elevation of one form of the engine, which is of 
the vertical inverted cylinder class, having the power cylinder a 
overhead. 

The piston b operates the crank shaft d by means of the piston 
rod c. The crank shaft operates in a closed chamber E, which 
chamber serves as a reservoir for gas and air mixture. Three 
ports are arranged in the side of the cylinder respectively, f, g, h ; 



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Gas Engines giving an Impulse for Every Revolution 291 

f is the charge inlet port admitting the charge to the cylinder, g 
is the exhaust port allowing the discharge of the exhaust gases 
from the cylinder, and h is the air inlet port to permit of the 
admission of air from the external atmosphere. The charge inlet 
port f communicates with the charge chamber e, and opens to the 



,'L 



tfnl rr\ £h— 




Fig. 112. — Day Gas Engine (vertical section). 

cylinder a opposed by the lip or projection 1 on the piston b. The 
exhaust port g connects by the pipe G l to the exhaust chamber 
G* of usual construction, and the chamber g 2 discharges to the 
atmosphere by the pipe g 3 . The air inlet port h connects by 
pipe h 1 to the base of the engine k, so as to quieten the air inlet 
The action is as follows. On the up-stroke of the piston b the 



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292 The Gas Engine 

pressure of the gases in the chamber e is reduced to about 3 or 
4 lbs. below atmosphere ; at or near the end of the up-stroke the 
lower edge of the piston uncovers the air inlet port h, and air 
rushes into the chamber to bring the pressure up to atmosphere ; 
gas is also admitted from the separate governor valve referred to, 
so that the chamber e becomes charged with a mixture of gas and 
air. On the down-stroke of the piston b the contents of the 
chamber e are compressed to 3 or 4 lbs. above atmosphere, and at 
the termination of the down-stroke the port f is uncovered as 
shown in fig. 112. The exhaust port g has been crossed by the 
piston b somewhat earlier in the down-stroke, sufficiently early to 
allow the hot gases from the previous explosion to discharge to 
atmospheric pressure before the port f is opened. The charge 
then flows from the port f under slight pressure, strikes against 
the lip or baffle plate or projection 1, and is deflected as shown by 

the arrows so that it flows 
in a stream to the end of 
the cylinder, then turns and 
fills the cylinder, expelling 
the exhaust gases by the 
port f. The piston b then 
returns on its up stroke, and 
Fig. 1 13. -Day Gas Engine (diagram). compresses the charge into 

a space at the end of the 
cylinder to a pressure of about 50 lbs. per square inch above 
atmosphere. The hot tube l then ignites the compressed charge, 
timing the explosion by the position of the incandescent part in 
a manner which will be explained more fully later on. The piston 
then makes its downward stroke under the pressure of the ex- 
plosion. By these operations an impulse is obtained at every 
revolution, as in the Clerk, Robson, and Stockport engines. 

Loss of power is caused by the absence of an inlet suction 

valve to the space e, and in later engines a suction valve is provided. 

This Day engine has the peculiarity, that it can be run in 

either direction; this is possible because of the absence of timing 

valves or valve gear operated from the crank shaft. 

Diagrams and Gas Consumption, — Fig. 113 is an indicator 




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Gas Engines giving an Impulse for Every Revolution 293 

diagram from this type of engine rated at 1 HP nominal. The 
diagram shows an indicated power of 3*3 horse at 180 revolu- 
tions per minute ; the cylinder is 4*5 ins. diameter and 7^ ins. 
stroke. The author has not obtained the gas consumption, but 
this seems no good reason why the results should be better than 
those obtained with Tangyes' Robson gas engine. That engine 
gave for the small powers a gas consumption of 40 cubic feet per 
brake HP with an average available pressure of about 45 lbs. per 
square inch. The diagram given shows an average pressure of 
about 45 lbs. per square inch, and is probably lower, as allowance 
should be made for the work of charging. 

General Remarks, — This engine appears to be the only remain- 
ing impulse-every-revolution engine now in the market in this 
country, and Messrs. Day & Co. are to be congratulated on their 
courage in adhering to the impulse-every-revolution type, and 
withstanding the temptation to desert and join the makers of Otto 
cycle engines. 

The author wishes Messrs. Day & Co. every success, but he is 
of opinion that further modification is required if results are to be 
obtained superior to the older Clerk, Robson, and Stockport 
engines. 

The Fawcett Gas Engine was manufactured by Messrs. 
Fawcett, Preston & Co., of Liverpool, and gave very fair results ; 
it does not now, however, occupy any prominent position in the 
market It is the invention of Mr. Beechy, and like the Clerk, 
Robson, and Stockport engines, it gives an explosion impulse at 
every revolution of the crank shaft. 

Fig. 114 is a sectional elevation of the engine ; fig. 115 is a 
sectional plan of explosion chamber and valves. 

The motor cylinder a is horizontal, and under it is arranged 
the pump cylinder b inclined towards the crank centre. The 
motor piston a 1 connects to the crank pin c by the connecting 
rod d, and the pump piston b 1 connects to a pin carried by the 
connecting rod d by the lower connecting rod e. The effect so far 
as the movement of the piston b 1 is concerned is practically the 
same as if the rod e were also connected to the crank pin c. The 



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294 



The Gas Engine 



piston b 1 thus reaches the in-end of its stroke a little before the 
piston a 1 , when the engine rotates in the direction of the arrow 
shown in fig. 114. The piston valve f, fig. 115, is operated from 
the crank shaft by an eccentric, and it serves to control the 
admission of gas and air to the pump cylinder b, and the dis- 
charge from the said cylinder to the motor cylinder a ; it also 
controls the admission of the compressed charge to the igniting 
tube k. A conical seat valve G, shown in dotted lines at fig. 114, 
controls the exhaust port h placed about the middle of the 




Fig. 114. — Fawcett Gas Engine (vertical section). 

cylinder, and the valve is actuated by a bell-crank lever 1 from a 
cam or eccentric on the crank shaft. The action is as follows : 
The piston valve f uncovers the port l leading by the passage L 1 
to the pump cylinder, the pump piston b 1 then moves forward 
drawing in a charge of gas and air, air by way of the pipe m, and 
gas by way of the annular port n, and the perforations or holes n 1 . 
When the pump piston has completed its outstroke the piston 
valve f closes the port l, and opens by way of the annular space 
between the two piston ends of the valve to the port o, which 
port communicates with the combustion space a 2 and cylinder a. 



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Gas Engines giving an Impulse for Every Revolution 295 

The piston a 1 is then on its instroke, together with the piston b 1 ^ 
and the exhaust valve g is held open so that the exhaust gases 
discharge into the atmosphere, and some of the charge enters 
from the pump and assists to displace them. When the piston a 1 
has crossed the exhaust port h, the greater part of the burned 
gases have been discharged, and part of the pump charge has 




Fig. H5.-Fawcett Gas Engine (sectional plan of combustion chamber). 

been forced from the cylinder b through the passage l 1 port l, and 
port o into the space a 2 ; the continued movement of the piston 
forces a further part of the charge into the working cylinder while 
compression is being caused by both pistons. When the piston b 1 
arrives at the in end of its stroke the piston valve moves to close 
the port l, as shown in fig. 115, and the piston a 1 further com- 
presses the charge. The continued movement of the piston 
valve f opens the incandescent tube k, and ignition takes place, 



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296 The Gas Engine 

driving the piston a 1 on its working stroke. The charge is ex- 
panded to the end of the stroke, and the exhaust valve is opened 
for the return. By this arrangement an impulse is secured at every 
revolution of the engine. 

Diagrams and Gas Consumption. — Experiments on the engine 

were made by Mr. T. L. Miller in 1890, from which it appears 

that in an engine indicating 11*49 HP at 150*8 revolutions per 

minute, 8-52 BHP was obtained with a gas consumption of 

18-4 cb. ft. per IHP per hour and 2474 cb. ft. per BHP per 

hour. The test was made with Liverpool gas, which evolves 

3996 lbs. Centigrade heat units per cb. ft. at 17 C, or heat 

equivalent to 555,490 ft. lbs. per cb. ft. If all the heat of the gas 

could be converted into mechanical work 3 564 cb. ft. would 

give 1 IHP for an hour. The absolute indicated efficiency of the 

. 1 n 3*564 x 100 
engine is therefore-— -g =19*3 per cent. 

General Remarks. — This engine closely resembles the Clerk 
type of engine in the arrangement of pump and motor piston, 
but it is subject to considerable difficulties in securing the dis- 
charge of the burned gases without simultaneously losing un- 
burned mixture of gas and air. The principal difficulty of all 
engines having open exhaust ports at the time of charging the 
cylinder lies in the proportioning and directing the flow of the 
entering gas and air to displace the burned gases without passing 
unburned gas away through this exhaust port In the Clerk engine 
this trouble was met by the long conical entrance and considerable 
length of cylinder for the sweep of the entering gases ; and in all 
engines such as the c Trent ' and the ' Fawcett,' where the power 
piston is discharging gases simultaneously with the entrance of the 
fresh charge, this trouble is increased, and it becomes necessary to 
leave large volumes of exhaust gases in the cylinder to avoid loss 
of gas at the exhaust ports. Mr. Beechey has succeeded very well 
indeed in minimising loss from this cause, as shown by the very 
fair results he obtains. He has the advantage of greater expan- 
sion than the • Otto ' type, although the disadvantage of greater 
proportion of exhaust gas brings down his economy. 



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297 



CHAPTER II. 

OTTO CYCLE GAS ENGINES. 

The ' Otto cycle engines are those which possess at present a 
living practical interest, and great advances have been made in 
them since 1886 ; in particular the gas consumption has been much 
reduced. The power of the engines constructed has also been 
greatly increased. In 1886 a nine-horse (nominal) gas engine of 
Messrs. Crossle/s construction consumed about 27 cb. ft. of Man- 
chester gas per brake horse power per hour, and now (1895) a 
similar engine consumes as little as 17 cb. ft. per brake horse 
power. The increase in power is also striking ; engines of 40 HP 
were the largest made in 1886, but now Otto cycle engines are 
built as large as 400 I HP. It is interesting to trace the steps 
which have made such improvement possible, and this will be best 
done by the study of the drawings of Otto cycle engines of recent 
construction. As the Messrs. Crossley are still the leading con- 
structors of gas engines in the world, turning out from their shops 
about sixty engines every week, the author will first consider one of 
their engines. 

Crossley Otto Engine.— Careful drawings have been made of a 
Crossley Otto engine of 9 HP (nominal) built in 1892, and now at 
work at the Clifton Rocks Railway, Bristol. The engine is num- 
bered 19772. It has been thought best to select an actual engine 
as an example in order to clearly appreciate the points of difference 
from the earlier engines. The particular engine selected was 
tested by the author for power and gas consumption. The engine 
shows many points of advance over the 1886 engines, but curiously 
enough, although it possesses all the necessary valve arrangements 
to enable high compression pressures to be utilised, yet defects 
in the proportion of the compression space and piston prevented 



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298 



The Gas Engine 



the use of high compression, and the engine did not give the best 
economy possible for* the particular type. Accordingly the gas 




o 

Ox 



Is 

a 

o 
O 



3 

I 

6 



consumed per brake HP hour was 25-9 cb. ft. This is a much 
better result than would have been obtained from a slide valve 



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Otto Cycle Gas Engines 299 

Otto engine such as illustrated on pages 167, 169 and 171 of this 
work, but it is not nearly so good as the type allows. 




Fig. 116 is a side elevation of the engine ; fig. 117 is a plan 
part in section; fig. 118 an end elevation; figs. 11 9- 123 inclusive 



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30Q 



The Gas Engine 



are drawn to a larger scale; fig. 1 19 is a side elevation of the back 
end of the cylinder looking on the cam shaft; fig. 120 is a corre- 
sponding plan; fig. 121 an end elevation; fig. 122 a vertical longi- 
tudinal section through the cylinder, and fig. 123 is a separate 
section on a still larger scale of the igniter tube and funnel 

A comparison of the illustrations with those of the earlier slide 
valve engine at once shows great mechanical development and 
points of constructive difference. Thus in the early engine the 
crosshead guide and the engine cylinder were two distinct parts 
requiring to be bolted together in accurate alignment in order to 

allow the piston with its cross- 
head slide to work freely without 
jamming : in the later engine a long 
trunk piston is used which serves 
the double purpose of piston and 
crosshead guide ; the separate 
crosshead slide is, in fact, dis- 
pensed with, and consequently the 
cylinder serves as its own slide 
guide, requiring no adjustment of 
separate parts. The cylinder, that 
is, serves both as cylinder and 
slide guide, and the whole cylinder 
is bolted to the bed against a 
powerful faced flange. 

The bevil wheels of the early 
design are also dispensed with 
and replaced by skew or worm wheels, which besides taking up 
much less space provide a much quieter drive for the two to one 
shaft. The unsightly distortion of the bed shown in fig. 51 neces- 
sary to admit the bevil wheels is quite avoided, as is clearly seen 
at fig. 117. There are many smaller points of constructive dif- 
ference which the experience of years has shown to be desirable, 
but the great points of departure are to be found in— the suppres- 
sion of the flame slide valve method of ignition, and the introduc- 
tion of the incandescent tube igniter; the diminution of the 
relative volume of the compression space, which is not carried out 
to its proper extent in this individual engine ; and the improved 




1 if* 

Fig. 118.— Crossley Otto Engine, 
9 HP Nominal (end elevation). 



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Otto Cycle Gas Engines 



301 



proportioning of the valves and ports in order to minimise the 
throttling of the charge during the inlet period and the back 
pressure of the exhaust gases during discharge. 

The engine follows the same cycle of operations as the old 
engine; that is, by one movement of the piston it takes into the 
cylinder a charge of gas and air which is compressed on the return 
stroke into a space at the end of the cylinder, there to be ignited 
in order to give the explosion and produce the power stroke ; the 
power stroke is then followed by the exhausting stroke, and the 



•VOaNi«« ICMITI*Wl 
»TAMTI«q •<!»•»•* CAM 




Fig. 119.— Crossley Otto Engine, 9 HP Nominal (side elevation, back end). 

engine is ready to go through the same operations to prepare for 
another power stroke. In this engine the charge of gas and air is 
admitted by the inlet valve 1, which is of the conical seated lift type ; 
the valve is operated by the lever j from a cam k on the valve shaft d. 
This valve shaft is rotated at half the speed of the crank shaft by 
means of worm wheels or skew gear e. The gas supply is admitted 
to the inlet valve 1 by the lift valve l, which valve is also operated by 
the lever and link n and cam m, controlled, however, by the centri- 
fugal governor s. The governor operates to either admit gas wholly 
or cut it off completely, so that the variation in power is obtained 



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302 



The Gas Engine 



by varying the number of the explosions. The exhaust valve f is 
also a conical seated lift valve, and it is actuated by the lever c 
and cam h. The ignition is produced by admitting a portion of 
the compressed inflammable charge from the compression space to 
the tube r, rendered incandescent by the Bunsen flame. The 







•TA«Tfft« ^•»lTl*W 



— ri 



**OAMIM« ^••lTI»M OP urn 

• 



ire 



Fig. i 20. — Crossley Otto Engine, 9 HP Nominal (plan, back end). 

passage to the igniter tube is controlled by the valve o, which 
valve is operated by the lever q and cam p. The valve o is double 
seated, and during the compression period of the engine the face 
nearest the compression space is kept up against the seat by a 
powerful spring; the incandescent tube is thus kept open to the 



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Otto Cycle Gas Engines 



303 



atmosphere, and notwithstanding any leak which may occur from 
the cylinder the tube remains empty until the moment when it is 
required for ignition. When the valve is lifted from one seat a 
small portion of the compressed mixture is discharged through a 
small port to the air, and this clears out the burned gases, 
which would otherwise render ignition irregular, and permits pure 




Fig. 121. — Crossley Otto Engine, 9 HP Nominal (end elevation). 

combustible mixture to reach the incandescent internal surface of 
the tube when the outer valve face closes on its seat. This device 
causes the ignition of the explosive mixture at the proper time. 

The adoption of lift valves for the admission and discharge 
of gases to and from the engine cylinder simplifies the 
practical problem of admitting and discharging with the least 
possible throttling or wire drawing. So long as slide valves were 



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304 



The Gas Engine 



used to admit the charge to the cylinder, it was difficult to provide 
a sufficiently large inlet area, as the area allowed in a port bearing 
against a slide surface determined the pressure necessary to hold 
the slide against the valve face to prevent the escape of flame 




:::::::;::::::::& 



when the compressed mixture was exploded. In a six horse- 
power engine of the old type, for example, the inlet port in the 
back cover was 2| inches long by g inch wide, equal to 1*5 square 
inches. Assume the maximum pressure of the explosion to be 



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Otto Cycle Gas Engines 



305 



T50 lbs. per square inch, then the slide valve must be pressed to its 
working face with a pressure not less than 225 lbs. ; as a matter of 
fact the slide was pressed up to its work with a pressure of about 
600 lbs. When it is considered that the flame temperature 
during the explosion is about 1600 C. it is easy to comprehend 
the difficulty of keeping the slide cool enough to maintain a good 
working surface even at comparatively low pressures. Designers 
of slide engines for this reason were forced to content themselves 
both with the minimum of port area and with low compressions. 
Small port area produced naturally considerable resistance to the 
inflowing charge, and low compressions prevented the attainment 
of any great economy of gas 
consumption. In the old 
engines, the velocity of flow 
of the air and gases entering 
the cylinder often exceeded 
244 feet per second, so that 
when the piston reached the 
out end of its stroke the 
cylinder was not filled up to 
atmospheric pressure. The 
evil of throttling in this way 
was not confined to the 
active loss of power due to 
the resistance to the charg- 
ing stroke of the piston ; the 
greatest loss was caused by 
the considerable reduction in the weight of the charge drawn in, 
and the consequent increase in the proportion of the exhaust gas 
present. In many cases it was found that the contents of the 
cylinder were at a pressure of 1^ lb. per square inch below atmo- 
sphere when the engine terminated its charging stroke, and this 
meant that the total volume of charge admitted was reduced by 20 
per cent, as compared with the charge which would have entered 
had the admission area been sufficient to allow the cylinder to fill 
up to atmospheric pressure. The proportion is greater because of 
the large volume of the compression space which must be 
allowed for in calculating the loss due to deficit of pressure. The 

x 




Fig. 123.— Crossley Otto Engine, 
9 HP Nominal (section of tube igniter). 



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306 The Gas Engine 

slide valve was undoubtedly a formidable difficulty in these 
engines, now happily overcome by the substitution of lift valves. 
With lift valves it is easy to provide any desired admission port 
area, as the pressure of the explosion holds the valve to its seat, 
and large valves may be used just as readily as small ones. In 
the engine illustrated in figs. 1 16-123 tne admission area is 6*52 
square inches, with the valve full open, and assuming maximum 
opening to remain during the whole charging stroke the velocity 
of the entering charge is only 87 feet per second. This engine 
is therefore better supplied with combustible mixture than the old 
slide engine. 

The compression pressure in a slide valve engine is limited by 
the difficulty of preventing a slide from cutting on its face at high 
compression and explosion pressures, and this difficulty is also 
overcome by the use of lift valves when combined with an 
incandescent tube igniter. 

In the older engines the importance of a free exhaust exit was 
not fully recognised, and although the exhaust valves were lift 
valves, the discharge area provided was insufficient Thus in the 
six-horse slide valve engine referred to, the average velocity of the 
exhaust gases past the exhaust valves was 137 feet per second ; 
in the present engine it is only 48 feet per second. The exhaust 
gases are thus better discharged in the recent engine. Any 
increase in the volume of the exhaust products causes loss of 
economy in a gas engine ; a small proportion does little harm, 
but a large volume of exhaust heats the entering charge and so 
raises the temperature of compression. Premature ignitions 
are also caused by the compression of a charge mixed with hot 
exhaust. Designers now endeavour to expel exhaust products 
as completely as possible. 

The engine illustrated has several bad points, and it appears 
to the author to be one issued by the makers while they were in a 
transition stage, probably engaged in increasing their compression 
pressures. To get the best possible results from a given volume 
of explosive mixture, it should be compressed into a combustion 
space, having the minimum of port capacity communicating with 
the admission and exhaust valves. In the older engines this 
point was not appreciated, and the port capacity was always 



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Otto Cycle Gas Engines 307 

excessive. In this engine the port capacity back to the exhaust 
and inlet valves is undoubtedly too great Ports act as con- 
densers for the flame of the explosion, and rapidly cool the ignited 
charge at a time when it least bears cooling. Any narrow spaces 
should also be avoided, and this engine presents an example of 
attempting to increase compression, by means of the block v 
attached to the piston, which should be carefully avoided- It will 
be noticed that the block v, fig. 117, projects into the combustion 
space through the reduced diameter part x, and so forms the 
annular space v between the piston proper and the reduced 
casing. This annulus has a cooling effect on the flame under the 
explosion pressure while the piston a is practically stationary, but 
it has a much more serious cooling effect whenever the piston 
begins to move out. The flame gases then pass through the space 
between the piston block v and the ring x into the annulus y, 
and so the flame is dragged through a cooling or condensing 
surface, and considerable loss is thus caused. Indeed it may be 
at once stated, that to gain the greatest advantage from high com- 
pressions the whole of the compressed explosive mixture should 
be contained in one space, that is a space which is not divided 
into smaller separate spaces. Ports should be avoided if possible, 
and the flame should never be caused to flow through a narrow 
space into a wider one, as is done in this engine. The compres- 
sion space should in fact be as nearly cubical or spherical as 
possible. Notwithstanding these defects, the engine shown in the 
illustration gives much better results than the old slide valve 
engines. For the purpose of comparison the author made prac- 
tically simultaneous tests on the engine illustrated and on an 
old slide valve engine of six horse power (nominal). The results 
obtained are given in the table on page 310, and all the important 
valve settings and numbers are also given. 

Fig. 124 is a diagram from the engine illustrated. It is a fair 
example of those taken during the test. 

Fig. 125 is the corresponding light spring diagram. 

Fig. 126 is a diagram from the slide valve engine which has 
been referred to, and fig. 127 is a light spring diagram also from 
the slide valve engine. 

The scales of the diagram figs. 124 and 126 are different, as 

x 2 



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3o8 



The Gas Engine 



one required a much stronger indicator spring. It will be ob- 
served that the slide valve engine only gives an available working 
pressure of 54*8 lbs. per square inch, while the lift valve engine 




Nominal HP, 9 ; diam. of cylinder, 9$" ; length of stroke, x8" ; revs, per min. 
160 ; indicated HP, 19*25 ; consumpt. per IHP per hour, 21*3 cb. ft. ; consumpt 
loose, 70 cb. ft per hour ; brake HP, 15*75 ' consumpt. per BHP per hour, 25*9 
cb. ft ; mean pressure, 81*5 lbs. ; max. pressure, 200 lbs. ; pressure before ignition, 
46 lbs. ; scale of spring, T b" per lb. 

Fig. 124.— Crossley Otto Engine, 9 HP Nominal (diagram). 

gives 81 -5 lbs. ; and on comparing the light spring diagrams it will 
be seen that with the slide valve engine the pressure falls consider- 



_25 




Scale of spring, ft" per lb. ; mean pressure, 2*5 lbs. ; charging resistance, 0*7 IHP ; 
total resistance running loose, 3 "3 IHP. 

Fie;. 125. -Crossley Otto Engine, 9 HP Nominal (light spring diagram). 

ably below atmosphere at the end of the charging stroke, while 
with the other engine the pressure rises nearly to atmosphere 
before the stroke terminates. 



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Otto Cycle Gas Engines 



309 



Crossley Otto c Scavenging' Engine, — The Crossley Otto engines 
now built differ to a considerable extent from the engine No. 



MR 548 LBS 




ISO 

■ 20 
100 [_ 
80 

60 
40 
20 



Nominal HP, 6 ; diam. of cylinder, 8'' ; length of stroke, 16" ; rev. per tnin. 164 ; 
indicated HP, 9 ; consumpt. per IHP per hour, 25*5 cb. ft. ; brake HP, 6*75 ; con- 
sumpt. per BHP per hour, 34 cb. ft. : mean pressure, 54*8 lbs. ; max. pressure, 
125 lbs. ; pressure before ignition, 32 lbs. ; scale of spring, &" per lb. 

Fig. 126. -Crossley Otto Engine, 6 HP slide valve (diagram). 

19772 which has been here discussed. Figs. 128 and 128A show 
the external appearance of the present engines. Fig. 128 shows 
the 30 HP nominal engine of 17 in. cylinder and 24 in. stroke, 



















f 




Id 

J 

<[■ 



(0 


»- 




. j 














~ 1 


': 





















' 













Scale of spring, T \ f " per lb. ; mean pressure, 3*85 ; charging resistance, 0*7 IHP ; 
total resistance running loose, 2*25 IH P. 

Fig. 127. — Crossley Otto Engine, 6 HP slide valve (light spring diagram). 

intended for ordinary driving and running at 160 revolutions per 
min. Fig. 12 8a is the 30 HP nominal electric lighting engine of 



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3io 



The Gas Engine 



Principal Particulars 

of a 6 NHP Crossley Otto Gas Engine, built about 1881, 

and a 9 NHP Crossley Otto Gas Engine, No. 19772, built in 1893. 



6 NHP Engine, No 468? ? NHP Engine, No. 1977a 
6" diam. cylinder x 16" stroke 94" diam. cylinder x 18" stroke 

-I ■ 



Volume swept by piston 
Volume of compression space. 
V ol. swe pt by piston 
Vol. of comp. space 
Compression pressure 

Explosion pressure . 

Mean available pressure 
Revolutions per minute . 
Indicated horse power . 
Brake horse power . 
Gas consumption per hour 

(including ignition) 
Gas per I HP per hour . 
Gas per BHP per hour . 
Mechanical efficiency . 

Area of charge inlet port 



Inlet port setting . 

Exhaust valve 
Exhaust valve setting 

Ignition lead . 



Charge velocity 
Exhaust velocity . 
Piston speed . . . 
Power absorbed charging and 
exhausting .... 
Gas inlet valve » 



Gas inlet valve setting . 



I 1 



804 cub. ins. 

516 cub. ins. 

8o4_ 1 

5i6~o-64 

H « 31 lbs. per sq. in. above 

( atmos. 

I 125 lbs. per sq. in. above 
i atmos. 

57 lbs. per sq. in. 

164 

9*0 

6-75 

j- 236 cub. ft. 

25*5 cub. ft. 
34 cub. ft. 
75 per cent. 

(Slide valve) 1*5 sq. in. 

I Is J" open when piston is I 
• on in centre, and A" open 
\ when piston is on out 
j centre J 

1 (2P diam. x §" lift) 2*65 
1 s»q. in. area 

/ Opens while piston is 1" \ 
' in from out end of stroke. ' 
- Closes when piston has - 
1 crossed in centre and 1 
I moved out £" ' 

' Ignition port in slide is an f 
-j i" open when crank is on •- 
J in centre 1 

244 ft. per sec. 
137 ft. per sec. 
437 ft. per min. 

07 IHP 

g" diam. x g" lift 



J When piston has made 1 \" 
forward stroke valve 
opens 



1275*8 cub. ins. 
510 cub. ins. 

Jf275'8 i_ 

510 "04 
48 lbs. per sq. in. above 
atmos. 

200 lbs. per sq. in. above 
atmos. 

81 '5 lbs. persq. in. 

19*25 

*5'75 

408 cub. ft. 

21*2 cub. ft. 
25*9 cub. ft. 
81 per cent. 
(Inlet valve 2$ ' diam. x J" 
lift) 6*52 sq. ins. 
Opens dead on in centre, is 
held open on out centre, 
and closes when the piston 
returns x\" in. At 1" in 
movement of piston the 
valve is ^" open 
(3" diam. xi \ fl lift) 11-78 
sq. in. area 

Opens while piston is 2J" 
from out end of stroke. 
Closes exactly on in centre. 



(Lift valve tube igniter) 
1 valve tV" dianux^V' Hft, 
opens i\" before compres- 
I sion is complete, but only 
full open \" before com- 
pression is complete 
87 ft. per se<\ 
48 ft. per sec. 
480 ft. per min. 

o' 7 IHP 

x"diam.xj"lift 
When piston has gone 2J" 
forward stroke valve opens, 
and does not close till out 
centre has been crossed and 
1 piston returns i{". _ Valve 
is -,*„" open when piston is 
j full out 



17 in. diam. cylinder and 21 in. stroke, which runs at 230 revolu- 
tions per min., and with coal gas will indicate a maximum power 
of 1 1 7 horse. The engines now supplied are of the ' scavenging * 



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312 



TJte Gas Engine 



type. The general external appearance is similar to that illus- 
trated, but an important modification is made in the operations 
performed by the engine. In addition to the cycle of operations 




8 

£ 

X 
o 



•c 

s 



a 

•a 

a 
W 

to 

c 

•a 






described, the engine is so arranged that the exhaust gases 
formerly remaining in the combustion space are swept out and 
the combustion space filled with air. The combustible charge in 
this engine is therefore a pure mixture of gas and air without any 



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Otto Cycle Gas Engines 



3*3 



exhaust gases. To accomplish this clearing out ot the burned 
gases and their replacement by air, advantage is taken ot the 
oscillations or waves of pressure set up in the exhaust pipe by 
the discharge of the exhaust gases. It has long been known that 
in a gas engine exhaust pipe the pressure of discharge is suc- 
ceeded by a partial vacuum, and this vacuum again succeeded 



Fig, lag. ; 




Fig. 129. — Crossley Otto Scavenging Engine (vertical section of cylinder). 
Fig. 130.- -Do. (sectional plan of cylinder). 

by pressure, in fact that under certain circumstances an oscilla- 
tion of pressure is set up in the exhaust pipe, giving a fall of 
pressure at certain periods after the exhaust valve is opened. 
Messrs. Crossley & Atkinson take advantage of this fact, and 
so control the pressure wave and the following vacuum that after 
the exhaust gases have been liberated from the cylinder of the 



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314 



TJte Gas Engine 



engine the high-pressure discharge is succeeded by a vacuum, 
the period of the vacuum coinciding with the approach of 
the piston to the end of its exhaust stroke. By then keeping 
open the exhaust valve and opening the charge or an inlet valve 
while the exhaust valve is open, a charge of pure air is drawn 



Fig. 131. 




Fig. 131. — Crossley Otto Scavenging Engine (end elevation). 
Fig. 132. — Do. (transverse section). 

through the combustion space to sweep out the burned gases from 
the compression, space. When the charging stroke is complete 
the whole cylinder is thus filled with a pure mixture of gas and 
air without the deleterious burned gases. To accomplish this 
sweeping out in a satisfactory manner it is necessary to shape the 
cylinder so as to favour the free flow of the entering air. 



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Otto Cycle Gas Engines 



315 



Figs. 129, 130, 131, 132 are, respectively, vertical section; sec- 
tional plan ; end elevation ; and transverse section illustrating the 
arrangement of a 4 HP nominal engine tested by the author at 
Messrs. Crossley's works in Manchester. 

Fig. 133 illustrates in a diagrammatic way the settings of the 
valves in that engine. 

The desired delay in the production of the vacuum is brought 
about by attaching an exhaust pipe c of about 65 ft. long. Quiet- 
ing chambers may be placed at the end of that length of pipe 
without affecting the result, but no large expansion or chamber 
should be put nearer to the engine cylinder. The energy of dis- 
charge of the exhaust sets the long column of gases filling the 
pipe in oscillating motion, and enables a considerable reduction of 
pressure to be produced just as the piston is completing its ex- 




Fig. 133. — Crossley Otto Scavenging Engine (valve settings). 

hausting stroke. Fig. 134 is a light spring diagram taken from the 
engine during the author's test, and it plainly shows the effect of 
the vacuum so produced in the exhaust pipe. It will be noted 
that at the termination of the exhausting stroke the pressure in 
the cylinder has fallen to 2 lbs. per square inch below atmosphere, 
a reduction of pressure amply sufficient to cause a flow of air from 
the atmosphere sweeping through the cylinder. 

On figs. 130 to 132 the arrows show the direction of the air 
current passing in by the inlet valve a through the specially shaped 
cylinder and out at the exhaust valve b. 

In fig. 133 the air inlet valve is opened while the crank is in 
the position d, and the exhaust valve is held open till the crank 
reaches the position b. The exhaust valve opens again at a, and 
it is held open to b position instead of as usual to c position. The 



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3i6 



The Gas Engine 



inlet valve is thus held open during the existence of a partial vacuum 
in the exhaust pipe, and so a ' scavenging ' charge of air is drawn 



29 

SO 

15 
10 



Fig. 

through 
air. 
Fig. 





-^ 













Scale of spring, A" per lb. ; charging and scavenging diagram ; 
charging diagram of 4 NHP Crossley Olto Engine. 

134. —Crossley Otto Scavenging Engine (light spring diagram), 
the combustion space and the products replaced by pure 
135 is a diagram taken by the author during his test of the 




per nun. 200 ; 
; brake HP, 11*97 ; 
*9 lbs. ; max. 



Fig. 135.— Crossley Otto Scavenging Engine (power diagram). 



scavenging engine at Messrs. Crossley's works, Openshaw. The 
leading particulars are marked upon the diagram, from which it 
will be observed that the engine gave results which were most 



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Otto Cycle Gas Engines 



317 



remarkable both from the points of power and economy. The 
engine, although only 7 in. diam. cylinder and 15 in. stroke, gave 
practically 12 -brake horse power on a gas consumption of 17 cb. ft. 
per brake horse power hour, a surprisingly good result for so small 
an engine. Openshaw gas is 20 candle power, and has a heat 
value of 53,000 ft. lbs. per cb. ft. 

Diagrams and Gas Consumption. — The diagrams given at figs. 
124, 125, 126, 127, 134 and 135 illustrate very fairly the progress 
made in the Crossley Otto engine from the old slide valve engine 
to the present lift valve scavenging engine, and it is interesting to 
compare the consumption of these three engines. They are as 
follows : 



Gas 
per IHPhour 



Slide valve engine 

Lift valve engine, No. 19772 

Lift valve scavenging engine 



25*5 cb. ft. 
21*2 cb. ft 
14-5 cb. ft. 



Gas I Compression 

per BHP hour P™*?™* P« ** j 
^ in. above atmos. I 



34 cb. ft. 30 lbs. 

25*9 cb. ft j 46 lbs. 
17 cb. ft. j 87 5 lbs. 



The advance made by the Messrs. Crossley is quite unmis- 
takable ; the brake consumption is now just about half of the 
consumption in a Crossley Otto engine built in 188 1. No doubt 
many of their slide valve engines were more economical than the 
one tested by the author, and the gas consumption of engine 
No. 19772 does not represent the most favourable result attained 
by the Messrs. Crossley before the advent of the scavenging engine. 
Thus the Crossley engine tested at the Society of Arts trials at the 
end of 1888 had a cylinder of 9-5 ins. diameter and a stroke of 
18 ins. The gas consumed per indicated horse power per hour 
was 20*55 c b- ft- an d per brake horse power 23*87 cb. ft. The 
compression pressure was 6i*6 lbs. per sq. in. above atmosphere. 
The indicated power was 17*12 horse, brake power 14*74 horse, 
and the speed of the engine 160 revs, per minute. The mean 
effective pressure was 67*9 lbs. per sq. in. and the initial pressure 
of the explosion 197 lbs. per sq. in. above atmosphere. 

The author's test of the 4 HP Crossley Otto scavenging 
engine was made in August 1894, so that, taking the Society of 
Arts Crossley engine as the most economical up to that date, from 



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318 The Gas Engine 

1888 to 1894 the Messrs. Crossley succeeded in reducing the gas 
consumption per brake horse power from 24 to 17 cb. ft. 

It is to be remembered that this figure of 17 cb. ft. per 
brake HP was obtained with a small engine. Mr. Atkinson, of 
Messrs. Crossley, has given the author results of a test made with 
an engine of n£ in. diam. cylinder and 21 in. stroke also at Man- 
chester. The power indicated was 46*8 horse, and the gas con- 
sumption was only 13-55 cb. ft. per I HP hour. The consumption 
of 1 7 cb. ft. per brake HP per hour is the lowest of which the 
author has experience with an engine so small. It will be observed 
that increasing economy in the Crossley Otto engine has always 
been accompanied by an increase of compression; thus a compres- 
sion of 30 lbs. in the slide valve engine of 188 1 has been displaced 
in 1894 by a compression of 87-5 lbs. 

Compression has evidently some part in securing the advan- 
tages of the present engine. Mr. Atkinson, in a paper read before 
the Manchester Association of Engineers, attributes the whole of 
the economy of the recent engine to the discharge of the burned 
gases and their replacement by pure air. In this the author does 
not agree with him ; he will, however, reserve the discussion of the 
matter to a general chapter upon gas engine economy, and he will 
now proceed to give a short account of the Otto engines of other 
makers. 

The Stockport Otto Engine.— Messrs. J. E. H. Andrew & Co. 
of Reddish now build a well-designed and carefully made Otto 
engine which they call the l Stockport Otto.' Figs. 136, 137 and 
138 illustrate its principal details. Fig. 136 is a side elevation of 
the cylinder and back part of the engine frame showing the back 
cover in longitudinal section through the admission valves. Fig. 137 
is an end elevation looking on the back cover, partly in section to 
show the igniting valve, the charging valve, and the exhaust 
valve. 

Fig. 138 is a section on a larger scale of the incandescent tube 
and the timing and starter valve. 

In fig. 136 the gas and air admission valve is shown nearest to the 
combustion space, the air to supply it being drawn along a passage 
cast outside the cylinder water jacket, from the bed of the engine, 
which serves as an air suction silencer. The gas supply valve is shown 



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Otto Cycle Gas Engines 



319 



outside the charge admission valve ; it is pressed down to its seat 
by a spring above it, and when it is lifted the gas from the gas pipe 




Fig. 136. - Stockport Otto Engine (side elevation). 




Fig. 137.— Stockport Otto Engine (end elevation). 

passes directly into the chamber under the charging valve and 
mixes with the air entering the cylinder. The gas valve is operated 



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320 



The Gas Engine 



by a lever similar to those shown in fig. 137, but the centrifugal 
governor shown in fig. 136 controls the lever by means of an inter- 
posing lever shown as connected to the governor sleeve. A 
short straight port communicates with the interior of the cylinder 
from above the charging valve. In fig. 137 the charging valve is 
again seen in section in the middle of the cylinder ; the exhaust 
valve is also shown in section at the left-hand side of the drawing ; 
both valves are brought to their seats by springs, and are operated 




Fig. 138.— Stockport Otto Engine (section incandescent tube and starter). 

by levers from the side shaft. In fig. 137 is also shown a section 
of the igniter tube and its timing valve. The timing valve opens 
into the port above the admission valve, and it is controlled by a 
lever and cam shown. From fig. 137 it will be seen that the exhaust 
valve is also connected to the cylinder by a short straight port. 
The section of igniter tube and starting valve, fig. 138, shows an 
incandescent metal igniter tube g, heated in the usual manner, 
but having a small internal tube passing into it from the space 



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Otto Cycle Gas Engines 



321 



controlled by the timing valve f. The valve a is used for starting, 
and will be described later on. The lever d opens the timing 



200 


P 




























MP 9l 8 LBS 








• 50 


















1 


<n 


•X, 


^2 ** * 


9 


i 




100 
SO 


/ 





















Nominal HP, ; diam. of cylinder, oJ"» length of stroke, 17" ; rev. per min. 184; 
constraint, per I HP per hour, 19 cb. ft. ; brake HP, ao*8 ; consumpt. per BHP per 
hour, aa*3 cb. ft. ; consumpt. loose, 63*6 cb. ft. ; mean pressure, 91*8 lbs. ; max. 
pressure, 230 lbs. ; pressure before ignition, 60 lbs. ; scale of spring, T ,V per lb. 

Fig. 139. — Stockport Otto Engine (power diagram, 60 lbs. compression). 



w 








MP 101 1 LBS 











O 


O 















N 


•O 


r^, 


•0 


s 





• 








Nominal HP, 9 ; diam. of cylinder, 9I"; length of stroke, 17" ; rev. per min. 183 ; 
consumpt. per IHP per hour, 17*6 cb. ft. ; brake HP, 24*4 ; consumpt. per BHP 
per hour, 20*75; consumpt. loose, 72 cb. ft. ; mean pressure, ioi'i lbs. ; max. 
pressure, 270 lbs. ; pressure before ignition, 90 lbs. ; scale of spring, T J '* per lb. 

Fig. 140.— Stockport Otto Engine (power diagram, 90 lbs. compression). 

valve f at the proper moment and admits compressed inflammable 
mixture from the port above the admission valve of the engine to 

Y 



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322 



The Gas Engine 



the tube g by way of the internal tube. The mixture then ignites, 
and the explosion is communicated to the cylinder. The chamber 
above the valve a serves to cause a sufficient rush through the 
tube g to make certain that explosive mixture reaches the incan- 
descent surface of the tube ; the valve f is held open long enough 
to allow the whole of the contents of the spaces and igniter to 
discharge into the exhaust valve so as to be ready for another 
explosion. 

Diagrams and Gas Consumption. — Mr. A. R. Bellamy of 
Messrs. Andrew & Co. has been good enough to send the author 
the diagrams, figs. 139 and 140, which have been taken by him 
from a Stockport Otto engine of the construction described. The 
engine had a cylinder of 9J in. diameter and a stroke of 1 7 in. 
The particulars of each test have been marked under the diagram. 





10 




































































u 

J 
< 


9 


5 

9. . 














































3 























Scale of spring, •£/' P* r lb. ; charging diagram from Engine No. 6242 at 60 lbs. 
compression. 

Fig. 141.— Stockport Otto Engine (light spring diagram). 

The diagrams are especially interesting, as they are taken from 
the same engine, but with a smaller compression space in the one 
case than in the other. In the first diagram the compression space 
is proportioned to give a compression pressure of 60 lbs. per square 
inch, while in the second the compression is 90 lbs. per square 
inch above atmosphere. The difference in economy is marked, as 
with the lower compression the engine consumed 19 cb. ft. per 
IHP hour, and with the higher compression only 17*6 cb. ft. per 
IHP hour. Fig. 141 is a light spring diagram from the same 
engine. 

Stockport Otto 400 HP Engine.— Messrs. Andrew & Co. have 
built perhaps the largest gas engine in the world, and they have 
kindly supplied the author with drawings from which the illustra- 



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Otto Cycle Gas Engines 



323 



tions, figs. 142, 146, have been prepared. The principal dimen- 
sions and a list of the parts are marked upon the figures. The 
arrangement of the engine is novel and interesting ; two cylinders 




y 2 



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324 



The Gas Engine 



are mounted, tandem fashion, on a bed plate. To avoid passing 
a piston rod through a combustion space the pistons are connected 
by a system of piston rods, crossheads and side rods ; both pistons 
thus connect to one crank shaft by a common connecting rod. 
Each cylinder operates on the Otto cycle, but the valves are timed 
to make the explosions alternate, and so an impulse is obtained for 
every revolution of the fly-wheel. 

The engine is applied to actuate a mill at Godalming, and it is 




Fig. 144.— Stockport Otto Engine, 400 1HP 
(end elevation with valve in section). 

supplied with gas generated by a Dowson plant. The maximum 
indicated power is stated to be 400 horse. The author has not as 
yet obtained indicator diagrams from this engine. 

Barker's Otto Engine. — In the examples which have been given 
of the Crossley and Stockport Otto engines it will be observed that 
both charging and exhausting valves communicate with the interior 
of the cylinder by ports of considerable dimensions. The ports in 
the Stockport engines are smaller than those in the Crossley ; 



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Otto Cycle Gas Engines 



325 



other conditions being similar, an engine where the whole of the 
mixture is contained in one large space, without small subsidiary 
spaces, is less liable to loss of heat at the maximum temperature 
of the explosion. It follows from this that if ports and passages 
can be avoided, then greater economy will be obtained. It is very 
convenient from a constructive point of view to build gas engines 
with ports, because it allows the charging and admission valves 
to be contained in separate casings, which can be bolted on the 
cylinder facings. Such casings also allow of the easy removal 
of the valves for cleaning, by merely unscrewing a light cover. 




Fig. 145. — Stockport Otto Engine, 
400 IHF (longitudinal section through 
exhaust valve). 



Fig. 146.— Stockport Otto Engine, 
400 IHP (longitudinal section through 
gas and air valves). 



Notwithstanding the great convenience of passages, it is important 
to dispense with them. 

Messrs. T. B. Barker & Co. of Birmingham have kept this 
point well in view in designing their Otto engine, which is illustrated 
at figs. 147-149. Fig. 147 is a side elevation of the engine with 
part of the cylinder in section to show the valve arrangements. 
Fig. 148 is a plan and fig. 149 is an end elevation. Here port 
surface has been practically abolished, as the valves are placed so 
as to open directly into the cylinder. The exhaust valve 1 and 
the charging valve 2 are carried in separate turned sleeves, which 
fit into bored recesses terminating at their inner ends in conical 



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326 



The Gas Engine 



valve seats. The sleeves are held up to their respective conical 
seats by a bridge piece 3 screwed on by the single nut 4. The 




ends of the bridge piece bear upon the ends of the sleeves, and on 
screwing up the nut 4 both sleeves are firmly pressed home. The 
valves are pulled to their seats by the spring 5 which also acts by 



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Otto Cycle Gas Engines 



327 



a bridge or stirrup. The valves are opened by levers 6, one of 
which, the admission valve, is here seen in the end elevation, fig. 149. 
The levers are operated by cams on the usual two to one shaft 




i 

1 



ft 

I* 
*1 



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rt S t. 

•IB 



ll si 












I 



i 



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J ".o 
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IH I 

".?:-<£ 

IB 

- > M 

211 

r.s'5. 

I U.S. 

h « « 

^■3-3 



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328 



The Gas Engine 



By this arrangement the upper surface of the exhaust valve i 
forms part of the interior surface of the cylinder, and so far as the 
exhaust valve is concerned the prejudicial port surface is abolished. 
The charging valve 2 also opens directly into the cylinder, but 
here it has been found advisable to allow the charge to enter the 
cylinder by way of a recess or cavity 7 } this recess, however, is very 
open, and does not appreciably increase the cooling surface. It 
has been found desirable to have a cavity 7 in order to make cer- 
tain of pure inflammable mixture for the igniting tube. This is 
the more necessary as the igniting tube operates without requiring 
a timing valve. 

The gas valve is shown 
at 8, fig. 149, and it is 
operated by the lever 9, 
the governor 10 controlling 
the gas supply in the usual 
manner. The ignition tube 
1 1 remains at all times open 
to the engine cylinder, and 
the time of ignition is ad- 
justed by the position of 
the incandescent part of 
the tube. To vary this 

iss,« ~ r» 1 — » r%^ » • position the Bunsen burner 

Fig. 149. — Barker's Otto Engine f 

(end elevation). 1S moved upwards or 

downwards as required. 
A very accurate adjustment of ignition is obtained in this 
way. 

The air supply is admitted to the annulus 12, and it passes 
through apertures in the sleeve carrying the admission valve. 
The exhaust gases are discharged by way of the pipe 13. 

The engine illustrated is of 12 HP nominal, and it gives 
excellent results, as may be seen from the accompanying dia- 
grams, figs. 150 and 151. Fig. 150 is a diagram taken with 
the engine fully loaded, and fig. 151 with the engine running 
light without load. The timing of the ignition when running 
without load is as perfect as when full load is carried. These 
two diagrams prove that the open tube igniter without timing 




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Otto C$cle Gas Engines 



329 



valve is quite capable of producing accurately timed explosions 
under widely varying conditions of temperature and composition 
of mixture. 

Diagrams and Gas Consumption. — An engine of the kind 
illustrated was tested at the Saltley Gas Works of the Birmingham 
Corporation at the beginning of 1894 by Mr. J. W. Morrison. 
Fig. 152 is one of the diagrams then obtained with the principal 
results of the test marked under it. From this it appears that 
the engine consumed as an average of four experiments 2 13 



300 



MP 76 LBS 




Nominal HP, 13 ; diam. of cylinder, 10" ; length of stroke, 18' ; revs, per min 180 ; 
indicated HP, 24 4 , consumpL per IHP per hour, 18 cb. ft. ; consumpt. per 6 HP 
per hour, 21 5 cb. ft. ; mean pressure, 76 lbs. ; max. pressure, 950 lbs. ; pressure 
before ignition, 51 lbs. • scale of springy rio" per lb 

Fig. 150. — Full Load Diagram. 12 NHP Barker Otto Engine. 

cb. ft. of gas per brake HP per hour, or 17*2 cb. ft. per IHP 
hour This is an admirable result with Birmingham gas. As the 
compression was only 50 lbs., it is evident that much of the 
efficiency of the engine was due to the very good arrangement of 
the combustion space and valves. This engine was designed 
for Messrs. Barker by Mr. F W Lanchester. In the author's 
opinion Mr Lanchester is to be congratulated on the excellence 
of the results. At the time the test was made the author believes 
the consumption to be the lowest then recorded. 

Tangyes* Otto Engine. — The Otto gas engine constructed by 



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330 



The Gas Engine 



Messrs. Tangye does not appear to have any features calling for 
special mention. In the smaller engines Pinkney's ingenious 



«300 




Scale of spring, -fa" per lb. ; rev. per min. 194 ; running light. 
Fig. 151.— No Load Diagram. 12 NHP Barker Otto Engine. 

momentum governor, described on page 235 of this work, is 
adapted to the Otto cycle, but in the larger engines the centrifugal 



iqo 




j - 
<Y 
o 
<dL 



Maximum brake HP, 30 ; diam. of cylinder, 12" ; length of stroke, 20" ; indicated 
HP, 36*6 ; consumpt. per I HP per hour, 17*7 cb. ft. ; brake HP, 99*8 ; consumpt. 
per BHP per hour, 21*8 cb. ft. ; mean pressure, 68*5 lbs. ; max. pressure, 180 lbs. ; 
pressure before ignition, 50 lbs. ; rev. per min. 207*25 ; scale of spring, -j-tu" per lb. 

Fig. 152. — Saltley Diagram. Barker Otto Engine. 

governor is used. The combustion chamber also is somewhat 
conical instead of being cylindrical. Indeed, Messrs. Tangye 
appear to claim special advantages in silencing the explosion by 



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Otto Cycle Gas Engines 



331 







H 

I 






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332 



Tfie Gas Engine 



means of this conical shape ; no doubt a conical chamber does 
possess certain advantages, and these advantages were fully 
appreciated by the author as early as the year 1880, as may be 
seen by examining the section of his engine on page 187 of this 
work. 

Messrs. Tangye's engine is well made, and the design is 
characteristic. Fig. 153 illustrates the general appearance of the 
engine, and fig. 154 is a diagram which Messrs. Tangye were 
good enough to send the author, giving the results claimed by 
them for a large gas engine. 




Nominal HP, 35 ; diam. of cylinder, 18" ; length of stroke, 24" ; rev. per man. 160 ; 
consumpt. per IHP per hour, 14*7 cb. ft. ; 3 explosions per cb. ft. of town gas; 
mean pressure, 89 lbs. ; max. pressure, 220 lbs. ; initial pressure before ignition, 

73 lbs. ; :»cale of spring, ,V'. 

Fig. 154.— Diagram from 35 NHP Tangyes' Otto Engine. 

Burt's Compound Otto Engine. — Many attempts have been 
made to utilise the compound principle in the gas engine in order 
to expand the compressed charge to a greater volume than that 
existing before compression. Otto, Crossley, Atkinson, Clerk 
and many others have experimented in this direction, but so far 
without success. The engine known as Burt's Acme Compound 
Engine is in reality an expansion engine and not a compound, as 
in it the full initial pressure is applied to both cylinders. That is, 
both pistons get the maximum pressure of the explosion ; the 



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Otto Cycle Gas Engines 333 

pistons between them, however, expand the compressed gases to a 
greater volume than their volume before compression, and so the 
engine is well worthy of study by engineers interested in some 
difficulties of compound gas engines. 

Professor W. T. Rowden, writing on a report on the engine 
giving the results of a test made in Glasgow, says : * The chief 
novelty in the engine is the method of obtaining expansion of the 
fired charge beyond the volume occupied by the mixed gases at 
the end of the intake portion of the cycle. 

' From the Otto and Clerk engines, and from others which are 
more or less copies of these two types, the products of combustion 
begin to escape whilst still at a pressure of from 30 to 40 lbs. 
above atmosphere. The "Acme" engine secures the desired 
expansion in a simple manner, and the exhaust is almost noiseless. 
Moreover, the temperature of the exhausted gases is so reduced 
by the cooling effect of the expansion as to remove all danger of 
fire from a heated exhaust pipe. Referring to the engraving 
of a 2 HP (nominal) engine [see fig. 155], it will be seen that 
two cylinders, pistons and shafts are used, the two shafts being 
connected by toothed wheels, which are geared in the ratio of 
2 to 1. The piston of the cylinder seen on the right, which is 
connected to the slow moving shaft, sweeps a less volume than 
the other does, besides making only half the number of strokes. 
This smaller volume is secured either by shortening the crank or 
lessening the diameter of the cylinder, or by the two combined. 
The two wheels are engaged so that when the fast-moving piston 
(on left) is at its outer and inner dead points, the other is distant 
from its dead points by a distance corresponding to a motion of 
about 45 degrees of its crank, an amount of travel corresponding 
roughly to one-seventh of the whole stroke. This piston regulates 
the firing and the exhaust by having the firing tube inserted 
through the cylinder at about one-seventh of its stroke from the 
inner dead point, and having ports opening from the cylinder at 
the outer seventh. Thus only one valve is required, namely, an 
automatic lift valve for admitting the charge of gas and air, and 
for preventing the formation of a partial vacuum in the cylinders 
when the engine misses an explosion by being governed.' 

B£ this clever device of two pistons operated by cranks geared 



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334 Ttte Gas Engine 

together in the ratio of two to one, the Acme engine succeeded in 
getting a considerable range of expansion beyond that given by 
other engines. 

Figs. 156, 157 and 158 are respectively side elevation, sec- 
tional plan and end elevation of a 12 HP nominal engine. 
The cylinder 1 is open at all times to the cylinder 2 by the 
wide short port 3, and the piston a in cylinder 1 makes double 




Fig. 155. — Burt's Compound Otto Engine. 

the number of strokes of the piston b in the cylinder 2. The 
crank a 1 connects to the piston a, and the crank b 1 to the piston 
b ; these cranks, as will be seen, have separate shafts, which are 
geared together by the toothed wheels c. The automatic lift valve 
4 admits a mixture of gas and air to both cylinders by way of 
the port 5, and and this valve 4 is supplied with gas by way of 
the valve 6 (fig. 156). The gas valve is controlled by the inertia 



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Otto Cycle Gas Engines 



335 



governor 7, which causes the blade 8 to miss the gas valve stem 6 
when it is necessary to cut out ignitions. The tube igniter 9 opens 
into the cylinder 2, and is uncovered at the proper time for ignition 




•J3 



I 

o 



I 



pq 
I 



2 



by the piston b ; that is about the position shown in the drawing, 
the piston b one-seventh on its forward stroke, and the piston a 
just on the in -centre. During the time the piston a is making its 
complete out-stroke, the piston b has moved out about f of its 



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336 



The Gas Engine 



stroke, and has uncovered the ports 10, which are the exhaust 
ports. These ports are cylinder ports such as were used in the 
Clerk engine. The pressure in both cylinders then falls to 
atmosphere, and the piston a makes its return stroke, while the 
piston b is uncovering the ports 10 and covering them again. The 



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piston b is just closing the ports io when the piston a completes 
its exhausting stroke, and the next out-stroke of a draws into the 
cylinder a mixture of gas and air by way of the automatic lift 
valve 4, and when the out charging stroke is completed the piston 
B covers the igniter tube port and does not uncover it till corn- 



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Otto Cycle Gas Engines 



337 



pression is completed. It is easy to see that by proportioning 
the stroke and diameter of the piston b to that of a, any desired 
expansion of the charge may be obtained. 

I'ig. 159 is a diagram from the cylinder 2, while fig. 160 is 
one from the cylinder 1, of a 12 HP engine similar to the 
illustrations, taken by Prof. Jamieson of Glasgow. The results of 
the test are marked under the diagram fig. 160. An examination 
of the two diagrams shows clearly the action of the engine. Com- 
pression begins when the piston b has nearly reached the end of 




^M 



ELX 



Fig. 158. — Burt's Compound Otto Engine (end elevation). 

its stroke and continues while the piston moves out from a to b, fig. 
159, that is the piston a is compressing its charge partly into the 
clearance space at the end of its cylinder and partly into the 
cylinder 2 by way of the port 3, so that the piston b is running 
away from the piston a, and is being followed up by the compres- 
sion. At b the charge ignites and the pressure rises to the same 
point in both cylinders, the piston b continues to move out and 
is followed by the piston a, which piston, however, speedily over- 
takes it, so that it finishes its stroke before the piston b moves out 
enough to uncover the exhaust ports 10 on the side of the cylinder ; 

z 



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338 



T/ie Gas Engine 



the pressure then falls to atmosphere very gently, as shown by 
the drop on the diagram fig. 159 at the point c. The diagram 
fig. 160 looks like an ordinary Otto diagram, but in interpreting 
its indications the diagram fig. 159 must be duly considered. 




Nominal HP, 12 ; short stroke cylinder, 10" diatn. x n" stroke ; spring x \$' per lb. ; 
max. pressure, 158 lbs. ; pressure before ignition at 6, 48 lbs. 

Fig. 159. — Diagram from Cylinder 2 Burt's Compound Otto. 

According to Prof. Jamieson's test of April 8, 1892, the 12 HP 
engine gave 13 brake HP on a consumption of 19*3 cb. ft. per 
brake HP per hour of Glasgow gas. 

Prof. Rowden made a test of a smaller engine of 6 HP 
nominal at the establishment of Messrs. Herbert Bros., corn 




Nominal HP, xa ; long stroke cylinder, ii|" diam. x 20" stroke ; rev. per min. 160 ; 
brake HP, 13 ; consumpt. per BHP hour, :q'3 cb. ft. ; max. pressure, 158 lbs. ; 
pressure before ignition, 48 lbs. ; scale of spring, T | u " per lb. 

Fig. 160. — Diagram from Cylinder I Burt's Compound Otto. 

merchants, Kennedy Street, Glasgow, and obtained 8*28 brake 
HP on a consumption of 17*3 cb. ft. of gas per brake HP 
hour, the faster crank running at 170 revolutions per minute. 
The * Acme Compound ' engine may therefore be taken to have 
consumed about 19 cb. ft. of Glasgow gas per brake HP hour ; 



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Otto Cycle Gas Engines 339 

this corresponds to about 21 cb. ft, of Birmingham gas, so that 
the results are very creditable. 

General Remarks. — This engine has been replaced by the 
Messrs. Burt's Otto engine of more usual type. The engine, 
although called compound, was not really a compound because 
both cylinders served as high and low pressure cylinders 
simultaneously. It seems to the author that an engine cannot 
be truly termed ' compound ' unless it includes separate high- 
pressure and low-pressure cylinders. The advantages to be ob- 
tained by the compound engine in saving weight and strength of 
engine cannot be gained without the use of a small cylinder to 
operate at high pressure and a large cylinder to operate at low 
pressure. This engine was necessarily heavy for its power, and it 

180 




Nominal HP, 6 ; diam. of cylinder. oi" ; length of stroke, 16" ; rev. per rain. 180; 
consumpt. per IHP hour, 1503 cb. ft. ; consumpi. per BHP hour. 20808 cb. ft. ; 
scale ot spring, r J 3 " per lb. ; max. pressure, 171 lbs. ; pressure before ignition, 
69 lbs. 

Fig. 161. — Diagram from 6 NHP Burt's Otto Engine. 

had the great disadvantage of requiring gear wheels, which wheels 
had to take the whole strain of the explosion. 

The engine is, however, very clever and interesting, and the 
author has described it at some length because of some lessons it 
teaches, which will be referred to in a later chapter, when com- 
pounding is discussed. 

Burfs Otto Engine. — Messrs. Burt & Co. now manufacture 
Otto gas engines of more usual construction, but instead of the 
ordinary lift valves they adopt a piston valve driven from the 
valve shaft by a small crank. They obtain fair results with those 
engines, as will be seen from diagram fig. 161, in which a 6 HP 
engine shows a consumption of 15*03 cb. ft. of Glasgow gas per 
IHP hour, and 20*8 cb. ft. per brake HP hour. It is to be kept 
in mind that Glasgow gas is of higher heat value than most 



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340 



The Gas Engine 



samples of English gas, but it is not so high now (1895) as it was 
in 1885, as the standard has been reduced. 




Fig. 162.— Burt's High Speed Otto Engine (vertical section). 

Messrs. Burt & Co. have recently built a high-speed gas 
engine, of which a vertical section is given at fig. 162, which is 
especially interesting, as it approaches so closely to steam engine 



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Otto Cycle Gas Engines 341 

lines. Two pistons 1 and 2 are arranged tandem fashion on the 
same piston rod 3 ; a common connecting rod 4 serves for both 
and actuates a crank 5. The upper sides of the pistons are used 
for the power impulses, and the lower sides operate idly moving 
air to and fro ; both pistons operate on the Otto cycle, but the 
impulses are arranged to alternate. The crank thus gets an 
impulse at every revolution when the engine is under full load. 
The crank shaft carries a wheel 6 gearing into a wheel 7, from 
which the piston valve is driven at half the number of strokes 
of the main crank. The action and function of these piston 
valves are very peculiar. The pistons 1 and 2, it will be seen, 
approach their cylinder covers as nearly as steam engine pistons, 
and the main combustion space is formed by the ports and pas- 
sages leading to the valves, and also by the annular space formed 
between the piston valve stems 9 and the cylinder. When the 
upper piston 1 is in the position shown in the figure, it will be seen 
that the cylinder is open to the annular space formed round the 
piston valve stem 9, and between the piston ports of the valve. 
These spaces form the combustion chamber, and the explosive 
mixture is compressed into them and ignited by the tube igniter 
10. When the piston 1 has made its power stroke down, the 
piston valve moves to bring into connection the ports 11 and 12* 
and the piston 1 then moves up and discharges the exhaust pro- 
ducts ; on the next down stroke the piston valve again takes the 
position shown by the upper valve, and the lower valve 13 is 
opened to admit a charge of gas and air on the next down stroke. 
The piston 2, as shown on the drawing, is just finishing its ex- 
hausting stroke, and the piston valve is about to close the exhaust 
port. The valve arrangements of piston 2 are similar to those of 
piston 1. 

This engine is most interesting for many reasons ; its designers 
are very daring, and appear to the author to disregard some of 
the understood conditions of gas engine economy. It appears to 
him impossible to obtain any high economy in gas consumption 
from an engine with its combustion spaces made up of tortuous 
ports and passages. The engine gives the designer an extreme 
example in the direction of subdividing the combustion space, 
and it will certainly be interesting to know its power and gas 



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342 



The Gas Engine 



consumption. Fig. 163 gives diagrams taken from the top and 
bottom cylinders at 400 and 480 revolutions respectively. 

Robtfs Otto Engine.— Messrs. Robcy & Co. now build Otto 
engines up to a brake power of 120 horse. 

Figure 164 shows their engine as made from 36 brake horse 

1200 



100 



20 




Top cylinder, 400 revs, per min. 



nfcie 



18 




Bottom cylinder, 480 revs, per min. 

Fig. 163. — Diagrams from Top and Bottom Cylinders, 
Burt's High Speed Engine 

to 120; the bed of the engine is of the Corliss type, and like all 
this maker's engines the design is pleasing and workmanlike. 
The exhaust valve opens directly into the combustion chamber, 
and so avoids port clearance spaces. This valve is removed by 
lifting a cap placed on the upper side of the cylinder and pulling 
the exhaust valve through, after removing the lever connections. 



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Otto Cycle Gas Engines 



343 




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344 TAe Gas Engine 

The charge inlet valve opens into a port at the end of the combus- 
tion chamber, and it also is removed by way of a cover placed 
above it. This system avoids the use of heavy sleeves which 
require to be taken out from below : such sleeves being very 
inconvenient in large engines. 

Ignition is effected by an incandescent tube, controlled by 
the usual timing valve. Messrs. Robey use a compression pres- 
sure of 60 lbs. per square inch. 

Wells Broth:r? Otto Engine.— Messrs. Wells Brothers build 
Otto cycle engines up to 1 20 HP. They make their engines of three 
main types ; the smaller engines up to and including 16 nominal 
HP are made on the usual Otto cycle without scavenging ; 
engines of 20 nominal HP and above are made with a scavenging 
arrangement to displace the exhaust products. The front end of 
the piston is enlarged and forms an annular cylinder which serves 
as an air pump. On the return stroke the air is discharged from 
the annulus, and passed through the combustion space of the 
cylinder so as to displace the burnt gases by pure air. For 
ordinary work the engine is made with a single cylinder, but for 
electric lighting two cylinders are used arranged in tandem. 
Fig. 165 shows in elevation an engine of the tandem type capable 
of indicating 120 HP with Dowson gas. The engine is con- 
structed and operates as follows. The front motor piston has a 
large end which works in the bored bedplate ; to this end the 
connecting rod is attached, so that it acts as a guide block. Two 
side rods are secured to the end and passed backwards alongside 
the cylinder liner through a passage way cast in the water jacket : 
thence they pass through bushes having light spring rings and 
secured at their rear ends to the crosshead of the back piston. The 
large piston acts as an air pump, but a free passage to the atmo- 
sphere is provided during the first part of the back stroke, so that 
the air intended for scavenging is only compressed and passed 
through the combustion chamber towards the end of the exhaust 
stroke. As the cylinders make exhaust strokes alternately, and 
the large piston forces air through the air passage leading to both 
cylinders at every back stroke, the air is discharged through 
whichever of the motor cylinders is in its exhaust stroke. 

The governor is of the high speed spring loaded centrifugal 



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Otto Cycle Gas Engines 



345 




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346 The Gas Engine 

type, and is driven by a bevil wheel on the crank shaft ; it controls 
upright hit and miss rods in such a manner that the gas is cut out 
from one cylinder before the other. The proportion of gas ad- 
mitted is also varied between narrow limits by graduated notches, 
which determine the lift of the gas valves. The engine has two 
flywheels and outside adjustable bearings, positive ratchet feed 
lubricators for the cylinders, and an oil box on the splash guard, 
and sight drop feed supply to the main bearings and to the crank 
pin by a centrifugal oiler. This engine is interesting, and it gives 
economical results. Messrs. Wells have supplied the author with 
the following particulars of a test made in their workshops with 
Nottingham coal gas : 

Test of a 60 BHP Wells Tandem Engine. 

Diameter of cylinders 12 inches 

Stroke 18 „ 

Speed 164 revs, per min. 

„ , . ( front 82 per min. 

Explosions tback , 8 

Mean effective pressure 90 lbs. per sq. inch 

Load on brake wheels 578 lbs. nett 

Circumference brake cin le . . . . 22*3 feet 

Gas consumption per hour .... 1. 190 cubic feet 

Indicated horse power 73 9 

Brake horse power 64*0 

Gas per IHP per hour 161 cubic feet 

Gas per BHP per hour 186 ,. 

These results are very satisfactory, and prove Messrs. Wells' 
engine to be an economical one. 

Fielding & Plaits Otto Engine.— Messrs. Fielding and 
Piatt build Otto cycle engines up to 200 indicated HP, the larger 
engines being of the tandem type. From the largest engine they 
obtain 170 brake horse power at full load, and by their system of 
governing for electric light purposes they claim that the maximum 
speed variation between running light and full load does not 
exceed three per cent. To accomplish this the engine is governed 
without cutting off the gas ; power impulses are given continuously, 
but reduced in strength to meet the variation in load. The gas 
and air supply valves are regulated separately, the governor 
reducing the gas and air simultaneously. The combustible mixture 



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Otto Cycle Gas Engines 347 

supplied to the engine is thus kept practically constant as to the 
relative amounts of gas and air, but the volume supplied is 
diminished and so reduces the compression. The compression 
varies from about 5 lbs. above atmosphere to 60 lbs. and ac- 
cordingly the explosion diagram varies within wide limits, so 
wide indeed that it is never necessary to miss impulses. The 
consumption is of course increased per indicated HP for light 
loads, but there are many cases where such increase is quite per- 
missible. The idea is one worthy of consideration where great 
regularity is required. 

Self-starting Gear. — Before leaving the mechanism of the Otto 
cycle engines, it is desirable to describe shortly the starting gears 
which are now used for such engines. The great increase in the 
power of the engines manufactured has made it imperatively 
necessary to provide starting devices which dispense with the old 
method of starting by hand. 

The first gas engine starting gear introduced in this country 
was the invention of the author, and was applied to the Clerk 
impulse-every-revolution engine, as described at p. 239 of the 
earlier part of this work. That starter required to store up air or 
gas and air mixture under compression, and this was found to 
involve expensive arrangements, so that although the gear was 
quite satisfactory in action its first cost was too high. 

The starting gear now the most extensively used is also the 
invention of the author ; the patent has been acquired by the 
Messrs. Crossley, and- the Clerk starter is now used by them in 
all engines of sufficient dimensions to require a starter. 

Fig. 166 is a diagrammatic section illustrating its action, a is 
the gas engine cylinder ; b a check valve opening into the exhaust 
port ; d a chamber connected by the pipe d 1 to the valve b ; and 1 
is an igniting valve, k is a port leading to a charging pump. 

The object of the device is to fill the combustion space of the 
engine with a compressed mixture of gas and air, and then to 
explode that compressed mixture and so provide a high-pressure 
explosion to give the starting impulse. 

To start : the engine crank is placed well off the centre ; the 
pump is operated by hand to fill the chamber d, pipe d 1 and 
cylinder a with gas and air mixture at atmospheric pressure, so that 



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348 



The Gas Engine 



no resistance is experienced during the operation of the pump. 
After charging, the igniter is operated, and the mixture in the 
chamber d ignites at the end near i ; the flame as it spreads 
through the chamber forces the unburned mixture before it into 
the pipe d 1 through the valve b into the cylinder a, so that when 
the flame arrives at the valve b it has swept before it into the 
cylinder all the unburned mixture, and when the flame passes the 
valve b it ignites the compressed mixture in the cylinder and 
produces a high-pressure explosion which starts off the engine 
with an ample margin of power to overcome the friction of 
belting and shafting. 

In conjunction with Mr. F. W. Lanchester the author has 




,tf 




Fig. 166.— Clerk Flame Starter. 

produced a modification of this starting gear which is known as 
Clerk-Lanchester starting gear, and it is illustrated in diagrammatic 
section at fig. 167. In this arrangement the igniting valve y is 
adopted, which is the invention of Mr. Lanchester. The pump 
for charging the starting chamber is also dispensed with. 

The action is as follows : When the engine is stopping, while it 
is making the last few revolutions with the gas turned off, the valve 
w is opened and air is drawn through the chamber d by way of 
the valve y at every suction stroke. The chamber d, pipe d' and 
cylinder a thus become filled with pure air at atmospheric 
pressure. When the engine is to be started the gas cock f is 
opened and gas flows from the gas main pipe at g into the cham- 



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Otto Cycle Gas Engines 



349 



ber d and at h into the pipe d', a cock on the cylinder being 
opened to allow flow into the cylinder, or the exhaust valve is held 
slightly open. The flame x burns across the valve y, and after a 
few seconds mixture of gas and air escapes through y and burns 
in the air. The cock f is then closed, and the flame shoots back 
past the valve y, and so ignites the mixture within d, closing the 
valve y against an upper face by the force of the explosion. The 
flame then proceeds along d, d' into the cylinder a, firing the mix- 
ture it has compressed before it, and so the engine is started by a 
compression explosion. 

Fig. 1 68 is a starting diagram obtained from this arrangement. 




Fig. 167. — Clerk-Lanchester Starter (diagrammatic section). 

From the diagram it will be observed that a maximum pressure of 
200 lbs. per square inch is attained, giving an available starting pres- 
sure of 80 lbs. per square inch, a pressure amply sufficient to start a 
gas engine, even allowing for the friction of a line of shafting. 

The great advantage of the Clerk or Clerk-Lanchester starter 
is due to the ease with which a compression explosion is obtained 
without the necessity of storing up compressed gases or compress- 
ing gases by manual labour. 

The Lanchester low-pressure starter is also extensively used 
when it is not considered necessary to obtain a high-pressure ex- 
plosion. Fig. 169 is a diagrammatic section of this starter, and 
fig. 170 is an indicator diagram showing the first and succeeding 



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3SO 



The Gas Engine 



starting explosions. The Lanchester low-pressure starter is un- 
doubtedly the simplest gas engine starting device which has ever 
been produced. It requires no addition to the engine save a gas 
admission cock and jet, and a mixture sampling and igniting cock. 



„200 




Fig. 168.— Clerk Starter Diagram. Initial pressure, 200 lbs. per sq. in. 
Average available pressure, 80 lbs. 

The engine cylinder a has mounted upon it the sampling and 
igniting cock 1 shown on a larger scale in section at 2 ; the cylinder 
is also supplied with a gas admission jet 3, fitted with a cock. 





Fig. 169.— Lanchester Starter (diagrammatic sections). 

When the gas is shut off to stop the engine the cylinder is filled with 
pure air, and so it remains filled with air at atmospheric pressure. 
When the engine is to be started, the crank is set well above the 
centre, the cock 3 is opened to the gas supply, the cock 1 is also 



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Otto Cycle Gas Engines 



351 



opened and the jet 4 is lit ; the gas then flows into the cylinder a, 
mixing with the air in the cylinder and displacing some air through 
the valve chamber b (section) ; in this chamber b is fitted a double- 
seated valve, which usually by its weight rests upon the lower seat ; 
grooves are cut round it and along its lower face to allow gases to 
flow past it while it rests on its lower seat. When the gas jet is 
first turned on air only flows through, but after a few seconds gas 
mixture follows and is ignited by the jet 4. The mixture burns as 
shown, and as it becomes richer in gas the flame changes its 
colour and burns with, a sharp roar ; the cock 3 is then turned off, 
and the flame shoots back into the cylinder and ignites the mix- 
ture existing at atmospheric pressure within it. The explosion at 
once slams the valve b against its upper seat and so closes it. The 
engine then starts under the pressure of the low-pressure explosion. 




Lanchester Starter Diagrams. 



At fig. 1 70 the diagram a shows the first explosion, and it will be 
observed that other diagrams b follow the first explosion. These 
explosions are produced by the action of the igniter. When 
the engine moves by the first explosion, the piston on its return 
discharges the exhaust in the usual manner ; on the next out-stroke 
it takes in the usual charge of gas and air. On the next return 
stroke, however, which would be the ordinary compressing stroke, 
the exhaust valve is held open during the whole stroke, and so the 
combustion space is left at the end of the stroke filled with a 
mixture of gas and air under no compression. During this back 
stroke some of the mixture flows through the jet 1, and is ignited at 
the flame, and so soon as the piston begins to move out again the 
flame shoots back, and another low-pressure explosion occurs, 
as shown at b> fig. 1 70. In this manner a series of low-pressure 



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35 2 The Gas Engine 

explosions are obtained sufficient to get up the speed of the engine 
to a point at which the compression may be safely applied and the 
engine caused to perform its ordinary cycle. The Lanchester 
starter is much used, and is very successful when the friction of 
the engine and its connections is not too great. 

Other Self-starting Devices, — The Lanchester and Clerk starters 
may be taken as the typical starters of to-day, and they are applied 
much more extensively than any other types. Most makers, 
however, now supply with their engines self-starters of some kind. 

Messrs. T. B. Barker & Co. and Messrs. Robey & Co. use the 
Lanchester starter. Messrs. J. E. H. Andrew & Co. also employ 
a low-pressure starter which resembles Lanchester's in its leading 
features. The igniting device is connected with the ordinary 
igniter tube. Fig. 138, page 320, shows this arrangement in section. 
The igniter tube g is fitted with an internal directing tube 
communicating behind the timing valve f. A gas supply cock 
with its jet somewhat similar to 3, fig. 169, is applied to the engine 
cylinder. When it is desired to start, the engine crank is set well 
off the centre as usual, the tube g is heated to incandescence and 
the valve a fig. 138 is opened to the atmosphere. The valve f 
is also opened in towards the cylinder. Gas then flows into the 
cylinder, mixes with the air within it as with the Lanchester 
device, and in entering it displaces air first and inflammable mixture 
afterwards past the valve f up the internal directing tube into the 
igniter tube g, then away in the direction shown by the arrows to 
the valve a and past that valve to the atmosphere. When the 
mixture becomes inflammable enough, the gas supply is cut off 
and the igniter tube ignites the mixture, then the valve a closes 
upon explosion. By this neat device Messrs. Andrew obtain their 
low-pressure starting explosion. The whole arrangement resembles 
Lanchester's except in the rather neat device for utilising the ordinary 
igniter tube c to obtain the starting explosion as well as the 
ordinary explosions. 

Messrs. Tangye adopt a somewhat more complex method of 
starting ; they set the engine crank on the in-centre, then pump a 
mixture of gas and air into the cylinder till the pressure approaches 
the usual pressure of compression ; they then simultaneously move 
the crank off the centre and admit the compressed charge to the 



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Otto Cycle Gas Engines 353 

igniter. They thus start with a compression explosion. This 
starter, it appears to the author, is open to the objection that in 
the event of a slight leak in the piston the man operating the hand 
pump may be unable to pump fast enough to obtain the necessary 
compression. 

Messrs. Fielding & Piatt utilise a starter which in one feature 
resembles the old Clerk starter described on p. 239. They cause 
the engine to compress air into a reservoir to a pressure of about 
60 lbs. per sq. inch and store this pressure up till wanted. To start, 
the engine is put off the centre and the cylinder is filled with pure gas 
or a mixture at atmospheric pressure so rich in gas that it is non- 
explosive. The air under pressure is then admitted to the cylinder 
and forms an explosive mixture under pressure, which mixture is 
ignited in the usual way by an igniter tube to give the starting 
explosion. 



A A 



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354 The Gas Engine 



CHAPTER III. 

THE PRODUCTION OF GAS FOR MOTIVE POWER. 

It has been already pointed out by the author in the earlier part 
of this work, that the unit of heat supplied in the form of ordinary 
coal gas is more costly than the unit of heat supplied in the form 
of coal, and that accordingly the gas engine remains at a disadvan- 
tage as compared with the steam engine till the time comes when 
the gas unit of heat costs no more than the coal unit. This fact 
has been recognised by many inventors, and numerous attempts 
have been made to produce cheaper gas. Mr. J. E. Dowson, 
however, is the only inventor who has made much headway in this 
subject, and his producers are now largely employed for generating 
gas for gas engines of large powers. Mr. Dowson has, however, only 
effected a partial solution of the problem, as his producers can only 
use two kinds of fuel, anthracite and coke. Of the two his pro- 
ducer acts better with anthracite ; with coke its performance cannot 
be said to be entirely satisfactory. The disadvantage of more 
expensive heat unit is not felt in small gas engines, because the 
governing of the engine and the heat efficiency is so much superior 
to any small steam engine that even in actual expense of fuel the 
gas engine is superior. The attendance required is also trifling 
compared with the steam engine. Accordingly it is quite un- 
necessary to trouble about gas other than towns gas for engines 
under twenty horse power. Engines giving out that power or any 
power above that and working steadily at full load require cheaper 
gas to compete with the steam engine. It would not be difficult, 
for example, to work a steam engine giving ioo horse power at 
3 lbs. of coal per IHP hour, the coal costing not more than 10s. 
per ton ; this gives an expenditure for coal of 016 penny per HP 



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The Production of Gas for Motive Pozver 355 

hour. A gas engine of 100 horse power would use about i£ lb. 1 
of anthracite costing 20s. per ton, and here the fuel would cost 
0-15 penny per HP hour. That is, assuming that the gas engine 
and producer cost as much for attendance, repairs and oil as the 
steam engine and boiler of corresponding power, it would just 
compete favourably with a steam engine using 3 lbs. of coal 
per indicated horse power. The gas engine, however, has a con- 
siderable advantage even when supplied by gas producers in 
working at light loads, and its consumption at such loads is 
proportionately less than the steam engine. If, however, gas 
producers could be made which would effectively produce gas 
from cheaper fuel, or fuel such as the slack generally used for 
steam boilers, then the gas engine would have an overwhelming 
superiority over the steam engine from a pecuniary point of view 
in large engines as well as small. 

The gas producer problem is, therefore, one which will doubt- 
less very considerably exercise the attention of inventors. Accord- 
ingly the author will now shortly discuss the principles of the 
subject, and then describe the Dowson and another producer and 
some of their difficulties. 

Ordinary town illuminating gas is produced by the destructive 
distillation of suitable coal. The object of the manufacturer is to 
produce a gas capable of burning with a bright illuminating flame. 
It is a purely accidental circumstance that such illuminating gas 
has also been found very suitable for generating motive power. 
Accordingly, it is not to be expected that coal gas should be gene- 
rated under the best economic conditions for cheap motive power. 
Gas-making coal is necessarily more expensive than the fuel 
ordinarily used in steam boilers, and further the process of destruc- 
tive distillation can only liberate from the coal such volatile 
matters as enter into its composition. The amount of gas so 
obtained per ton of coal depends on the temperature of distillation, 
or the temperature of carbonisation as the gas engineers call it. 
At a comparatively high temperature a larger volume of gas is given 
off per ton, but the percentage of illuminating gases present are 
reduced, and so the illuminating power is low. A good gas coal 
on destructive distillation will yield at a fair carbonising temperature 
1 Under I lb. per IHP hour has been claimed by Mr. Dowson. 

A A 2 



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356 TIu Gas Engine 

from 10,000 to 11,000 cb. ft. of gas per ton of coal of from 15 
to 17 candle power, and it will leave in the retort about 62 to 73 
per cent, of coke ; that is, of 100 tons of the original gas coal 38 
to 27 tons are driven off as illuminating gas, vapour, tar, ammonia, 
water, &c, while 62 to 73 tons remain in the retort as coke. So 
long, then, as the ordinary process of destructive distillation is 
adopted, the heat unit of coal gas supplied to a gas engine must 
necessarily be more expensive than the heat unit evolved in the 
furnace of a steam boiler, because more fuel and that more expen- 
sive fuel is required apart altogether from the cost of the distribu- 
tion of the gas from the gas works. To compete with the steam 
boiler and furnace in producing a gas heat unit as cheaply as a 
coal heat unit placed on the fire grate, it is necessary to convert 
the whole of the coal into gas suitable for use in a gas engine. 

At first glance it appears a difficult problem to produce inflam- 
mable gas from solid carbon either in the form of anthracite or of 
coke, but the principle is simple enough. When unit weight of 
carbon is entirely burned in air or oxygen, carbonic acid, or more 
properly carbonic anhydride, is formed, that is the gas CO a . This 
gas C0 2 if passed through a sufficient depth of incandescent carbon 
is converted into the gas carbonic oxide, which is inflammable. The 
chemical reaction is generally given : 

C0 2 +C=2CO. 

That is, two volumes of CO a combined with a sufficient weight 
of carbon to form carbdnic oxide produce four volumes of carbonic 
oxide gas. For the purpose of the gas engine using a properly 
proportioned gas generator it may be considered that the carbon 
used is burned to carbonic oxide only and not to carbonic acid. 
The heat evolved in the process of producing carbonic oxide 
from carbon is 

Unit weight of carbon forming CO evolves 2400 heat units, 

but 

Unit weight of carbon forming C0 2 evolves 8000 heat units, 

so that the process of the formation of carbonic oxide loses a part 
of the heat of the carbon, and the same weight of carbon in 
carbonic oxide will only produce when the carbonic oxide is 
burned 5,600 heat units instead of 8,000. Thus by passing air 



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The Production of Gas for Motive Power 357 

through incandescent carbon or coke of a sufficient depth, carbonic 
oxide gas can be formed and the whole of the carbon transformed 
into an inflammable gas. The air on first coming into contact 
with the incandescent carbon burns a portion of it to C0 2 , carbonic 
acid gas, and this carbonic acid on passing through a further body 
of incandescent carbon is reduced to the inflammable gas carbonic 
oxide, CO. The first stage of the process evolves all the heat of 
combustion, and the second stage absorbs a portion of the heat 
so evolved. The net result is that if the inflammable gas produced 
be cooled down and then burned in a gas engine cylinder, the heat 
evolved by the combustion will only be 70 per cent, of the heat 
which the solid carbon would have evolved if burned directly with- 
out preliminary conversion into gas. The 30 per cent, of heat is 
carried away by the carbonic oxide from the gas producer, and is 
lost on cooling down the gas to suit it for use in the gas engine. 
When air is blown through the producer the nitrogen of the air of 
course remains, and is mixed with the inflammable CO. This is 
the fundamental idea of the gas producer, and accordingly it will 
be found that the earlier and abortive proposals for the conversion 
of the entire solid fuel into gas contemplated only blowing air 
through a sufficient depth of carbon. Taking the composition of 
atmospheric air as 4 vols, nitrogen and 1 vol. oxygen (the new 
element argon may be neglected, as it is included in the nitrogen 
and is very similar to it), then the best gas which could be produced 
in this simple manner would be that in which the whole of the 
oxygen was used up in forming carbonic oxide. Remembering 
that 1 vol. of oxygen gas after combining with enough carbon to 
make CO forms 2 vols, of that gas, the composition of the gas 
proceeding from the producer would be 4 vols, nitrogen and 
2 vols, carbonic oxide, thatns : 

4 vols, nitrogen = 66 '6 per cen 

2 vols, carbonic oxide = 33 '3 

ICO'O 

The gas obtained would consist entirely of 66*6 per cent, of 
nitrogen and 33*3 per cent, of carbonic oxide ; this gas on com- 
bustion in the engine would evolve 70 per cent, of the heat of the 
original carbon. That is, if the efficiency of the producer be 
compared with a steam boiler, it would be equal to that of a boiler 



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35 8 The Gas Engine 

giving 70 per cent, of the heat of combustion in its furnace in the 
form of steam delivered at the stop valve. 

Such a producer, however, would waste an entirely unneces- 
sary amount of heat, and would give considerable practical difficulty 
in getting rid of the 30 per cent, of the heat of all the carbon 
gasefied in it, the lining would be overheated, and generally the 
temperature of the carbon contained in the producer would be- 
come undesirably intense. A certain high temperature is required, 
it is true, to convert the C0 2 into CO, but if that temperature be 
maintained it is undesirable to go above it Gas engineers have 
accordingly taken advantage of another chemical reaction to use 
some of this heat and produce better gas. If steam be passed over 
highly incandescent carbon, which carbon must, however, be kept 
incandescent, the oxygen of the steam unites with the carbon, and 
the hydrogen of the steam is liberated. The ultimate effect of the 
reaction is to decompose steam and produce hydrogen and carbonic 
oxide ; the reaction is as follows : 

H 2 + C=H 2 +CO. 

That is, 2 volumes of water vapour in contact with incandescent 
carbon produce 2 volumes of hydrogen gas and two volumes of 
carbonic oxide gas. This reaction, however, absorbs heat to pro- 
duce the decomposition of the steam ; more heat requires to 
be absorbed than is given out by the burning of the carbon 
to CO. 

To decompose steam containing 2 units weight of hydrogen 
gas requires the absorption of 68340 heat units, and in producing 
28 units weight of CO from 12 units weight of carbon there 
are evolved 28800 heat units ; that is, the heat evolved by the 
carbonic oxide produced in the reaction is about one-half of the 
total heat required. This reaction cannot therefore proceed 
without a sufficient supply of heat from some source ; the best 
source is the formation of CO by means of air also acting on the 
carbon. To supply heat just sufficient to perform the reaction 
would require the heat evolved in producing 1 vol. CO by air and 
carbon to every 073 vol. of CO produced by the reaction of 
steam on carbon. The composition of the gas so produced 
would be : 



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The Production of Gas for Motive Power 359 

CO- 4 V °l } P"^ 110 ^ b y tne re 8101 * 011 of the oxygen of the air on carbon. 
H- X ' 4 fi V °i I P roduced bv tne reaction of steam upon carbon. 
8-92 vols, total. 

The percentage composition would be about : 

N- 45-0 

CO= 390 

H=* x6o 



The production of a gas of this composition assumes that all the 
heat is utilised for the purpose of the reaction and that none is 
lost from the apparatus. It assumes also that all the heat carried 
away by the gas after formation is returned to the air and steam 
which are about to perform the reaction. This is of course im- 
possible, but the calculation has been made in order to supply a 
standard of comparison. Such a gas would contain the whole of 
the heat of the original carbon before gasefying. In an actual 
apparatus the carbon is placed in a brick-lined producer ignited and 
blown up to a good heat by a forced draught ; the producer is 
then closed, and steam and air blown in in definite proportions to 
pass through the incandescent carbon mass. The resulting gas 
passes away from the producer in a heated state and is cooled 
before being sent into the gas holder. The reaction requires a 
certain temperature for its continuance, so that the interior of the 
producer must not fall below it ; the gas is discharged at this 
temperature, and so a greater supply of air is necessary than that 
calculated to make up for the heat losses. 

Dowson Gas Producer. — The Dowson gas producer at present 
embodies in the best way the fundamental principles and the con- 
structive details necessary for the production of gas from solid fuel ; 
that is, gas suitable for a gas engine. 

Fig. 171 is a diagrammatic section of a Dowson gas producer 
with its accompanying gas holder. Fig. 172 is an elevation part 
section, and fig. 173 a plan of a gas producer in its building with 
all the necessary parts to form a complete plant. 

Referring to fig. 171, the producer consists of a cylindrical 
casing a lined with fire brick or fire clay, and having at the 



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36o 



The Gas Engine 



bottom fire bars a above a closed ash pit b ; the upper part of the 
generator is closed by a metal plate on which there is mounted a 
fuel hopper a 1 having an internal bell valve a 1 operated from the 
exterior. To begin operations, the upper cover is removed from 




Fig. 171. — Dowson Gas Producer and Gas Holder 
(diagrammatic section). 

the hopper a 1 and the bell valve is opened ; a fire is built upon 
the bars a and air forced through it by the steam jet n and the 
pipe n 1 ; fuel (anthracite or coke) is slowly added from above till 
the whole mass is incandescent and fills the producer to a depth 



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The Production of Gas for Motive Power 361 

of about 18 inches at least. During this heating up process, gases 
are given off by way of the open hopper, and they are ignited 
there by means of a flame. Great care must be taken not to 
inhale the issuing gas, as it contains large quantities of carbonic 
oxide and is very poisonous ; it should always be ignited when it 




SECTIONAL ELEVATION 

Fig. 172.— Dowson Gas Producer (part in section). 

flows into the producer room, as when burned it becomes harm- 
less. When the fuel is quite incandescent, the inner and outer 
valves of the hopper are closed and the gas flows by a pipe 
through cooling and scrubbing devices, finally finding its way into 
the gas holder k through the coke scrubber formed within it. 
From the gas holder the gas flows through another scrubber, as 



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362 



The Gas Engine 



shown by the arrow, fig. 171, and thence passes to the engine. 
The gas holder k is of usual construction with annular water seal 
and balance weights, chains and pulleys. 

The complete plant for 80 HP effective is shown at figs. 
172 and 173, where a is the small steam boiler fitted with 
superheating tubes, which boiler supplies superheated steam to 
operate the air injector b and so forces a mixture of steam and air 




GENERAL PLAU. 

Fig. 173.— Dowson Gas Producer (plan). 

through the incandescent fuel contained in the gas generator c. 
Fuel is fed to the generator by the feeding hopper d, and the gas 
formed flows from the upper part of the producer in the direction 
shown by the arrow to the gas cooler f, whence it passes to the 
hydraulic box h, which box is provided with an overflow 1, and 
thence the gas proceeds to the sawdust scrubber j, and then to 
the coke scrubber k contained within the base of the gas holder. 
In these figures, e is the generator fire grate, l the gas holder, m 



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TIu Production of Gas for Motive Power 363 

the outlet from the gas holder, nn the ash pit for the generator, 
and o the automatic regulator to govern the production of gas by 
stopping or reducing the supply of steam with the upward move- 
ment of the gas holder. 

From this description it will be seen that the whole plant is 
very simple, and the author can say from his own experience that 
it is easily operated and requires little repair. One man can easily 
attend to an 80 HP plant. 

The gas produced from the Dowson producer is thus a 
mixture of carbonic oxide, hydrogen, and nitrogen ; if all the 
actions were carried out perfectly there would be no carbonic acid 
gas present, but as all the actions are not quite up to theory some 
carbonic acid is formed. A little sulphuretted hydrogen is also 
formed, more with coke than with anthracite, and this has to be 
removed, as sulphur in quantity would in time act on the engine 
parts. 

The following analysis of Dowson gas was made by Prof. 
Wm. Foster ; the anthracite used in the producer was of the 
cheapest kinds in small pieces : 

Standard 
Analysis of Dowson gas, by volume gas 

(ideal) 

Nitrogen, N 48*98 .... 45*0 

Carbonic oxide, CO . . .25*07 

Hydrogen, H 1873 

Marsh gas, CH 4 .... '31 

defiant gas, QjHj .... '31 

Carbonic acid, CO a . . . . 6*57 
Oxygen, O '03 

XOO'OO 

Comparing this with a perfect producer gas, it is seen that 
instead of getting 39 per cent, of carbonic oxide by volume only 
25*07 is obtained ; on the other hand, when the ideal gas would only 
give 16 per cent, of hydrogen 1873 per cent, has been obtained, 
and a further 0*62 per cent of marsh gas and olefiant gas. The 
marsh gas and olefiant gas are produced doubtless from the small 
quantity of hydrogen which forms part of the original anthracite ; 
anthracite contains about 3 per cent, of hydrogen. The excess .of 
hydrogen, however, in the gas can only arise from the fact that the 
whole of the carbonic acid original! v formed is not reduced to 



. 390 

44*42 . . 16*0 



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364 The Gas Engine 

carbonic oxide. This is evident from the fact that 6*57 per cent of 
carbonic acid is present. As the burning of carbon to carbonic 
acid instead of to carbonic oxide involves the evolution of the 
whole 100 per cent of the heat of combustion of the carbon instead 
of only 30 per cent, of it, it follows that more heat is left available 
for the decomposition of water by the coke, less carbonic oxide 
is formed by the action of the oxygen of the air on the carbon, 
and so the proportion of carbonic oxide in the gas diminishes, 
while that of hydrogen increases. A French analysis of Dowson 
gas is as follows ': 

Analysis of Dowson Gas produced in France. 



Nitrogen, N 



Carbonic oxide, CO . 
Hydrogen, H 
Hydrocarbons, {£"* } 

Carbonic acid, C0 4 . 
Oxygen 



42 28 



I8-20 V 

26 * 55 [ 45 '86 combustible. 



xi 30 
0-47 



Here it will be observed that the nitrogen is still lower, and 
that notwithstanding the great increase of carbonic acid gas, 1 1 '3 
per cent instead of 6-57 per cent, the hydrogen gas has increased 
from 1873 P er cent - t0 2655 per cent, while the carbonic oxide 
has gone down from 25*07 per cent to 18*20. This disproportion 
between the hydrogen and carbonic oxide can only arise from the 
fact that carbonic oxide itself at a high temperature decomposes 
steam, so that part of the carbonic oxide which would otherwise 
have appeared in the mixture has disappeared, forming carbonic 
acid and hydrogen ; the reaction is : 

CO+H 2 0=C0. 2 + H 2 . 

That this is true is evident from both analyses, where there is 
present a considerable proportion of carbonic acid, in one case 
6*57 per cent, and in the other 11 -30 per cent. ; it is to be observed 
that the increase of hydrogen is accompanied by an increase of 
carbonic acid. 

It is often stated that hydrogen is a gas of greater heating 
power than carbonic oxide, but as a matter of fact for gas engine 
purposes this is not so ; hydrogen, it is true, weight for weight 
evolves far more heat by its combustion than any other substance, 



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The Production of Gas for Motive Power 365 

but volume for volume carbonic oxide evolves rather more heat 
than hydrogen. Hydrogen evolves by the combustion of 1 lb. 
weight 34170 heat units, or enough heat to raise 34170 lbs. of 
water through i° C, but this figure includes the heat evolved on 
liquefying the steam, formed by the combustion, in the calorimeter, 
which at 637 heat units per lb. of water gives 9x637=5733 
heat units absorbed in forming steam produced by burning 1 lb. 
of hydrogen. So that from 34170 heat units must be deducted 
5733* that is 34170- 5733=28437- 

This number 28437 is the available heat produced by the 
combustion of hydrogen for the purpose of a gas engine. Now, 
unit weight of carbonic oxide evolves 2400 heat units, and unit 
volume weighs 14 times that of unit volume of hydrogen, so that 
to get the relative heating effects of equal volumes of carbonic oxide 
and hydrogen this difference in weight must be allowed for. 
The heat evolved by unit volume of CO is therefore 2400 x 14= 
33600; that is, volume for volume carbonic oxide evolves 1*18 
times the heat of hydrogen. Hydrogen and carbonic oxide may 
therefore be taken on an analysis of gases by volume to be nearly 
equal in gas engine value. The percentage of total combustible 
material may be taken roughly as representing the relative heat- 
ing value of two gases : from this it appears that the French analy- 
sis of Dowson gas, notwithstanding the high percentage of CO 2, 
represents the better gas of the two, as the English sample has 
444 per cent, combustible and the French sample 45*9 per cent 
The French author gives the efficiency of the producer as 75 per 
cent. ; that is, the gas will give 75 per cent, on combustion of the 
total heat which the original fuel would have given. If it were 
certain that the analysis represented the composition of the gas as 
it left the producer, then the efficiency could be calculated from the 
analysis itself ; but as the gases pass through scrubbers and coolers 
before reaching the gas holder, and thereby lose carbonic acid and 
water vapour, it is impossible to calculate the efficiency of the 
producer with accuracy from the analysis. 

Dowson gas of the composition given at page 363 requires for 
the complete combustion of 1 cb. ft. as nearly as possible 0*24 
cb. ft. of oxygen or 1*13 cb. ft. of atmospheric air ; that is, 
Dowson gas requires for its combustion a little more than its own 



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366 The Gas Engine 

volume of air. From Table III. in Appendix II. it will be seen 
that in samples of illuminating coal gas from twenty different gas 
works in Britain the proportion of air required for complete 
combustion varied from 5*19 vols, to 7*40 vols, of air; that is, 
1 cb. ft. of coal gas required in one town only 5*19 cb. ft. of air 
for its combustion, while 1 cb. ft. of the gas of another town 
required 7*40 cb. ft. of air. 

The heat evolved by t cb. ft. of Dowson gas is about one- 
fourth of that evolved by an average gas, such as Birmingham gas, 
so that the amount required in a gas engine cylinder is about 
four times what would have been required with coal gas. For a 
gas admitted to the cylinder in the proportion of 1 of coal gas to 
8 of mixture of gas and air, it would require 4 of Dowson gas, but 
this would leave too little air for combustion. Consequently till 
very recently the diagram obtained in a gas engine cylinder from 
Dowson gas did not give so high an average pressure as coal gas. 
In ordinary practice, according to the author's experience, it was 
not safe to rely on an average available pressure of more than 
50 lbs. per sq. in., while coal gas easily gave 70 lbs. By using, 
however, Messrs. Crossley and Atkinson's new scavenging engine, 
enough air can be introduced to burn a larger quantity of Dowson 
gas, so that now an average available pressure of 65 lbs. per 
sq. in. can be relied upon in such an engine using Dowson gas 
and giving about 40 I HP ; in larger engines higher available 
pressures may be obtained, and in smaller engines lower 
pressures. 

To secure the good and economical working of a gas engine 
it is absolutely necessary that the gas supplied to it should be of 
fairly uniform quality, otherwise the engine, which is adjusted to 
draw in gas and air in a fixed proportion, may at one moment 
be taking in a gas of such richness that the air allowed is in- 
sufficient for combustion, and at another time the gas may be so 
poor that the air is too largely in excess, and so a weak explosion 
or no explosion at all is obtained. 

One of the advantages of a fixed carbon fuel, such as anthracite 
or coke, with little or no volatile matter, is that when such fuel is 
added to the generator no gases are given off by destructive 
distillation. In the Dowson generator, fig. 1 7 1, if such gases were 



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Tfie Production of Gas for Motive Power 367 

given off at each charging with fuel, then they would find their way 
direct into the gasometer and practically fill the gasometer with 
gases such as CH 4 , C 2 H 4 and pure H to such an extent as to 
render the gas much too rich to be burned in the gas engine 
cylinder with the proportion of air allowed for the ordinary 
Dowson gas. The addition of anthracite or coke produces no 
such disturbance; further the composition of the incandescent 
charge in the generator remains fairly constant until it is wholly 
consumed, so that there is no variation from that cause. Again, if 
ordinary flaming coal be added to the producer, large quantities 
of condensible carbon compounds, such as tar, would be given off, 
and the scrubbing and purifying would be much more difficult. 
Altogether the Dowson apparatus, although it solves the problem 
in an easy and practical manner, limiting its fuel to anthracite and 
coke, does not do so for the cheaper but more troublesome fuels 
used under the ordinary steam boiler. The percentage of heat 
obtained, however, from the gas generated, 75 per cent, of the 
original heat of the fuel, compares satisfactorily with the 
efficiency of an ordinary Lancashire steam boiler without 
economisers. 

Lencauchez Gas Producer. — The Lencauchez producer is not 
to the author's knowledge in use in England, but it is reported 
favourably upon by Professor A. Witz and others in France. It 
is an attempt to improve upon Dowson's producer in such manner 
as to save some of the heat at present lost with the highly heated 
gases leaving the producer, to get back in fact some of the heat 
which at present is entirely lost by cooling the gas ; and further 
to make such producers suitable for use with fuel, such as 
slack or other fuel giving off considerable quantities of volatile 
carbon. 

Fig. 174 is a vertical side section, and fig. 175 is a front 
elevation part in section of this producer, a is the gas generator 
lined with fire brick, b is the grate and c the closed ash pit, n is 
the feed hopper with upper and lower door or valves, E is a bridge 
passing down from above and causing the gas to flow from about 
the middle of the producer instead of from the top, K is the gas 
discharge passage, which first passes up through the brickwork and 
then passes up a flue or tube formed through two cylindric.nl 



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368 



The Gas Engine 



Fia 175. 







Jfr*frgn *- f r fj: fTi eK tmr y 



Fig. 174. — Lencauchez Gas Producer (vertical side section). 
Fig. 175. — Lencauchez Gas Producer (front elevation, part section). 



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The Production of Gas for Motive Power 369 

vessels or chambers respectively G and H. The lower vessel g is 
an air and steam heater, the upper is a boiler. From the upper 
vessel the gas passes to the gas holder by the pipe 1 ; k is a valve 
at the top of the branch to allow the gas to be ignited and sampled 
at any time either at starting or during operation. The action is 
as follows : The generator is started much in the same way as 
has been described for Dowson, but the hot gases ascending the 
tube or passage f heat the vessels g and h, steam is formed in h, 
but without pressure, and it flows into the casing g by way of the 
pipe h 1 : air is forced into the casing g from the pipe l by means 
of a fan or other positive blower, it mixes with the steam proceed- 
ing from the upper vessel and both are considerably heated, the 
air then flows by the pipe m shown in dotted lines to the closed 
ash pit c. The heated mixture of air and steam passes through 
the incandescent fuel in the generator, forms carbonic oxide and 
hydrogen and passes up the passage f. The fuel meantime which 
is in the upper part of the generator a is by the heat from below 
being subjected to destructive distillation, and the gases formed, 
as they cannot escape by the hopper, pass down through the 
incandescent fuel and then escape by the passage f with the other 
gases. This descent through the incandescent fuel is stated to 
have the effect of splitting up all the tarry matters contained in 
the volatile gases and fixing the gases in permanent form as CH 4 , 
C 2 H 4 and H. The fuel does not reach the incandescent part 
until it is thoroughly coked. By this arrangement of separating 
the freshly charged fuel from the incandescent fuel and passing 
the hot gases away from a part of the generator which contains 
nothing but incandescent fuel, it is stated that the difficulty of 
using fuels such as common slack is avoided. 

The producer is ingenious and worthy of careful study, but 
the author is of opinion that with such fuel it will be found that 
the system of destroying the tar and coking the fresh fuel is not 
sufficiently perfect, and that dirtier gas of irregular composition 
will be fed to the engine. With anthracite or coke, however, the 
Lencauchez producer will work well and give some economy over 
the Dowson. 

According to Richards this producer with French anthracite 
gives gas of the following composition : 

B B 



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37° 



The Gas Engine 


Analysis op Lencauchez Gas (Anthracite). 


Nitrogen, N . 


• 47 '84 


Carbonic oxide, CO 


. 27'32\ 

34 1 48 46 combustible, 

1-25 1 


Hydrogen, H 
Olefiant gas, CH 4 . 


Hydrocarbons, C 4 H 4 . 


• i'SS> 


Carbonic acid, C0 2 


. 360 


Sulphur dioxide, S0 2 . 


o'04 


Sulphuretted hydrogen, H<jS 


o*o6 



According to Richards the loss due to gasefying is only 13 per 
cent. ; if this be true, then the efficiency of the producer is 87 per 
cent., a higher efficiency than any standard test of a steam boiler. 
The gas is considerably better than the best analysis shows Dowson 
gas to be ; but the author, although he can understand some 
advance in Dowson practice, cannot see that so much can be 
gained by the apparatus illustrated as to increase the efficiency 
from 75 percent, to 87 per cent. However, Lencauchez' apparatus 
is a step in the right direction and is worthy of careful consideration. 

The tar difficulty in gas producers for gas engines is a very 
serious one, and even with Dowson's apparatus more tarry matter 
reaches the engine than when town gas is used. This neces- 
sitates frequently cleaning the valves. A very little tar getting to 
the valves soon makes them work with difficulty, and so deranges 
the whole action of the engine. 

Other Gas Producers. — Several gas engine makers now manu- 
facture gas producers themselves, notably Messrs. Tangyes Lim. 
and Messrs. Dick, Kerr & Co. Lim., but the general principles 
involved are those common to the Dowson and Lencauchez 
producers, so that at present till more experience has been gained 
it is needless to discuss their points of departure. Many gas pro- 
ducers which are used for ordinary furnace work such as Siemens' 
and Wilson's, are not applicable to gas engine work because of the 
tarry nature of the gas given off and the comparative irregularity 
of its composition. 

Water gas, too, is sometimes stated as useful for gas engines, 
but from an examination of tests with water gas plant it appears 
that although the gas obtained is much richer in combustible 
material, the loss in making it is greater than that with producer 



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Tke Production of Gas for Motive Power 37 1 

gas. Water gas is produced by blowing steam upon white hot 
coke, when the steam is split up, as described, into carbonic oxide 
and oxygen ; after a short time the carbon loses heat, and air is 
blown in to heat it up again. The gases leaving the generator in 
this blowing-up process give up their heat as they leave by passing 
through a regenerator, which regenerator is used to heat up the 
entering steam and air on the next process. In this way gas is 
obtained with but little nitrogen. 

Water gas is extensively made in America for town supply, and 
in this country also it is now considerably manufactured by the gas 
companies to mix with ordinary coal gas. 

The water gas, however, although it works a gas engine quite 
well, and many gas engines in America do use it, is not interesting 
from the point of view of competing with the steam boiler. 

Fuel Consumption of Gas Engines with Producer Gas. — 
Mr. Dowson made a test with a Crossley Otto engine of 60 HP 
nominal, using his producer gas, for which he claims the very 
low fuel consumption of 0762 lb. of anthracite and coke 
during a working test of eight hours. Allowing for the total loss 
of fuel in the generator standing all night and also clinkering, the 
consumption is only brought up to 0*873 lb. per IHP hour. 

The engine was of the well-known Crossley Otto two -cylinder 
type. The leading particulars of the trial are as follows : 

Nominal power of engine . 60 HP 

Diameter of cylinders 17 ins. 

Length of stroke 24 ,, 

Duration of trial 8 hrs. (9.40 A.M. to 5.40 P.M.). 

Total revolutions of crank shaft during trial . . 74751 = 15573 per minute. 
,, explosions in left cylinder .... 25908= 53975 

t. ». right cylinder . . 26619 a 55'45 6 ,. 

.... . ^. Jt r 79'q left cylinder. 

Mean available pressure on indicator diagrams . \'-. Q r :~ut 

78*9 average of both. 

, . . . f 59'3 left cylinder. 

Mean indicated horse power during trial . • 1 -«.. -i «,»,#■ 

59 4 ri S ai »• 

1 18 7 

Mean temperature of gas in bags near engine . 67 F. 

,, ,, air to engine 50 F. 

,, ,, water overflow from left cylinder 125 F. 

,. right ,, . ii9°F. 

,, ,, feed water of boiler .... 75 F. 

B B 2 



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37 2 The Gas Engine 

Mean pressure of gas in holder i£ in water. 

M ,, steam in boiler 48 lbs. 

Anthracite l consumed in generator during trial .... 584 lbs. 

Coke* ,, ,, boiler to get up steam before trial . . 30 „ 

Coke consumed in boiler during trial 140 ,, 

Anthracite consumed during trial . . 0*615 lD * P 61, IHP working hour. 

Coke „ ,, 0*147 •» 11 »» 

Total . 0762 ,, ,, t , 

Anthracite put in generator on morning after ) 

trial to make up for loss during 9 night r 0*058 ,, „ ,, 

hours 56 lbs. ' 



Anthracite put in generator on following \ 

50 lbs. 



morning after raking out clinkers &c. I- 0*053 



Total loss during night and after clinkering) . 

106 lbs f 0111 " 

Total consumption of anthracite and coke! . g 

during trial and following night . . )°J*73 •• »» >» 

Gas consumed 3 at rate of about 63 cubic feet per IHP per hour. 
Anthracite consumed during trial, about 10 lbs. . Per 1,000 cubic feet of 

Anthracite and coke consumed during trial, about 12 lbs. > gas made. 

W ' t ^n , Jta? lfar CO ° Ung the l6oogaltonsperhour= S o-slbs. per IHP per hour. 

Water used for boiler . .10 ,, ,, = o*8 ,, ,, 

Water used for cleaning gas 14 ,, ,, = i'i ,, ,, f , 

Total water used during trial 624 ,, ,, =52*4 ,, ,, ,, 

Total water used for gas-making . . . J 3' 2 gallons per 1 ,000 cubic 

I feet of gas made. 
Oil used for cylinders during trial .... i$ pint at as. $d. per gallon. 

„ bearings „ , i\ „ is. qd. ,, ,, 

Coal gas 5 used for heating ignition tubes . . 4^ cubic feet per hour. 
/ x pair stones (4 feet diameter) 24 elevators. 



Machines 

worked 

during 

trial. 



13 ,, rolls (250 revolutions) 2 exhaust fans. 

4 ,, disks (600 revolutions) sundry conveyors. 

14 ordinary silks pump. 

7 centrifugal silks shafting, &c. 
4 purifiers. 



1 Anthracite used was the usual kind from the Gwaun Cae Gurwen Colliery 
Company, Limited. 2 Coke from Gas Light and Coke Company. 

5 Rate of gas consumed was measured by shutting the inlet of gas holder and 
timing the fall of the holder through 6 feet, while the engine was working. 

4 All the water used was pumped up from the river by the engine, and run to 
waste. Usually the water used for cooling an engine flows to and from an over- 
head tank. 

5 Coal gas was used for this purpose, because Dowson gas could not be taken 
from the main supplying the engine, and there was no .separate outlet from the 
gas holder. 



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The Production of Gas for Motive Power 373 

This is a valuable test as showing the best consumptions of fuel 
to be obtained with Dowson gas in an engine giving off about 
120 HP indicated, but it is of course lower than would be 
obtained in ordinary work with the plant handled by the ordinary 
engineer. 

It is to be noted also that the level of fuel in the generator was 
estimated as the same at the end as at the beginning of the eight hours' 
test. The author considers it rather dangerous to estimate the fuel 
remaining in this way ; great errors might easily creep in by this 
practice. The only accurate method is to empty the generator at 
the start and weigh out all the fuel for filling up and starting, then 
to rake out the fuel remaining and damp it out and weigh at the 
end of the test. 

In 1890, Prof. A. Witz tested a Simplex gas engine of 100 
HP at the Paris Exhibition, and found with Dowson gas a fuel 
consumption of 1*34 lb. of English anthracite per brake HP hour. 

A recent test of an Otto engine of 100 HP with two cylinders 
was made at Philadelphia by Mr. H. W. Spangler, using producer 
gas made in a producer somewhat similar to the Lencauchez under 
Taylor's American patent. The efficiency of the producer was 
found to be 69*1 per cent. ; that is, the gas produced by it would 
produce on combustion 69-1 per cent, of the heat which could be 
got by burning the original fuel put into it. The engine indicated 
130 horse and consumed 1*315 lb. of coal per IHP hour. The 
coal used in the producer gave the following analysis : 

Analysis op Coal used in Spangler's Test. 

Moisture 4*20 

Volatile and combustible carbon and hydrogen .6*88 

Fixed carbon 80*41 

Ash 851 

Sulphur 074 

10074 

This coal is evidently inferior to English anthracite, so that 
the result of 131 lb. per IHP is very fair. Allowing for ash 
and moisture, the combustible matter burned was only 0*830 lb. 
per IHP hour. 

The author tested an Otto engine recently with Dowson gas, 
and found in a seven and a half hours' test a consumption of 



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374 



The Gas Engine 



1*87 lb. of anthracite and coke per IHP. The engine indicated 
23*5 horse power at 210 revolutions. Fig. 176 is a diagram 
from the engine on that occasion, with the leading particulars 
marked under it. 

In this case, however, the author considers that better results 
would have been obtained if the producer had supplied two engines 
instead of one ; the consumption of anthracite in the generator, 



* a 8 * g t 



-10 



Nominal HP, 14 ; diam. of cylinder, 11*5" ; length of stroke, 21}" ; revs, per min. 
axo; fuel per IHP hour, 1*87 lb. (anthracite and coke); indicated HP, 3V5 ; 
BHP, 27 "5 ; mean pressure, 58*4 lbs. per sq. in. ; max. pressure, 200 'lbs. ; 
pressure of compression, 83 Its. above atmosphere. 

Fig. 176.— Crossley Otto Scavenging Engine (diagram with Dowson gas). 

about half a hundredweight per hour, was too little for maximum 
efficiency. 

From these tests, then, it may be considered as absolutely 
established that in ordinary work the consumption of anthracite 
in a good Otto engine using Dowson or a similar gas ranges from 
1 1 lb. per IHP for an engine of about 30 IHP to 1 lb. for an 
engine of 130 IHP. 




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375 



CHAPTER IV. 

THE PRESENT POSITION OF GAS ENGINE ECONOMY. 

In this chapter the author will discuss the fuel consumption of the 
gas engine at present and the economy obtained since 1886 ; he 
will examine the various causes of the advance with the object 
of understanding the direction of progress, and if possible of 
indicating the lines still open for improvement. 

The Crossley Otto engine has made wonderful progress in 
reducing gas consumption since 1886, but for the purpose of com- 
parison it is desirable to go back to 1882 ; at the latter date the 
Crossley engine gave an indicated horse power hour on 237 cb. ft. 
of London gas of such heating power that the indicated efficiency 
of the engine is E=o*i7, that is 0*17 of the whole heat supplied 
to the engine appears on the diagram as indicated work. 

In 1888 the engine submitted by Messrs. Crossley for the 
Society of Arts trials consumed 20*55 c ^. ft. per IHP hour of 
London gas of a heating value of 483270 ft. lbs. per cb. ft. Cal- 
* culating from this and reducing the gas measurements for tempera- 
ture and pressure, the indicated efficiency becomes 0*21. At the 
end of the year 1888 it may be taken that the best result obtain- 
able from an Otto engine of about 1 7 IHP was a conversion of 02 1 
of the heat given to it into indicated work. 

The third test taken for comparison was made by the author 
at Messrs. Crossley's works, Openshaw, on August 31, 1894, on 
an engine of 7 in. diameter cylinder and 15 in. stroke. This 
engine developed at 200 revs, the great power of 12 brake horse 
and indicated 14 horse or a consumption of 14-5 cb. ft. of Open- 
shaw gas per IHP hour and 17 cb. ft. per BHP hour. 

Taking the heating value of Openshaw gas as 530000 foot pounds 
per cb. ft. at 17 C. and 147 lbs. pressure, the indicated efficiency 



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376 TJie Gas Engine 

is 0-25 ; that is, the engine converts 0*25 of all the heat given to it 
into indicated work. This is an extraordinarily good result, much 
better, in fact, than any result ever obtained before to the author's 
knowledge. To make certain that there was no mistake, the author 
had the gas meter tested and the brake weights and measurements 
all carefully checked in his presence. 

The Messrs. Crossley have, therefore, made a very substantial 
improvement in the economy of gas since 1882, and it is interesting 
to note that each step of diminished gas consumption is attended 
by an increase in compression ; this is very evident from the table 
below. 

Absolute indicated Efficiency of Crossley Otto Engines 
of similar size since 1882. 

it a,.:....,... Pressure of compression 

Efficiency abovc atmo8 £ here 

(1) 1882-88 017 . 38 lbs. per sq. in. 

(a) 1888-94 021 . 66-6 lbs. „ „ 

(3) 1894 ... . 025. 87-5 lbs. „ „ 

The experiments giving efficiencies under (i) and (2) were 
made with engines of 9 in. diameter cylinder and 95 in. diameter 
cylinder respectively, both engines having 18 in. stroke, so that the 
engines may be considered to be of the same dimensions so far as 
change of economy due to change of dimensions is concerned. The 
result (3), on the contrary, was obtained with an engine of 7 in. 
diameter cylinder and 15 in. stroke, so that 026 would more pro- 
perly represent the efficiency to be obtained from an engine of 
the same dimensions as in the other experiments. 

From these numbers it is evident that economy increases with 
increased compression, but now the question arises : Does the 
increased compression completely account for the improved per- 
formance ? If the calculated result from the various compression 
pressures accounts for the whole change of gas consumption 
accompanying change of pressure, then it is evident that to the 
increase of compression is to be credited the improved economy. 

To test this the author has calculated by formula 10 on p. 53 
the theoretical efficiency of an air engine in which no practical 
losses occurred, the air engine having the same proportion of com- 
pression space as the actual gas engines. Those theoretical 
efficiencies are shown in the table below placed beside the actual 



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T/ie Present Position of Gas Engine Economy 377 

efficiencies obtained in the gas engine ; a column is also given 
showing the ratio between the ideal and actual efficiencies, and 
other columns showing the dimensions of the engines, the gas con- 
sumption per IHP hour, the ratio of compression space to volume 
swept by piston, and the pressure of compression in pounds per 
square inch above atmosphere. 

Theoretic indicated Efficiency of Crossley Otto Engines with 

DIFFERENT COMPRESSIONS COMPARED WITH ACTUAL INDICATED 

Efficiencies with the same Compressions. 



E= calculated 
efficiency for perfect 
Otto cycle engines 
from compression 

space volume 


E= actual indicated 

efficiency from 

1 diagrams and gas 

consumption 


Ratio of 
actual to 

ideal 
efficiency 


'•0 

4 

.5 


V 

1 

w 

k 

•0 

c 


of compression 1 
to SDace swept ■ 
by piston 


If 

H 


1 § I 








5 


6 


Ratio 
space 




1 Sk 








ins. 


ins. 




lbs. 


] cb.ft. 


(l) 0'33 


0*17 


33 


9*0 


18 


06 


38 


1 ** 


(2) 0*40 


o*2I 


40 


9"5 


18 


04 


616 


^ 


(3) 0-428 


025 


•428 


70 


15 


o'34 


875 


14*8 



From this table it is evident that the improved economy is 
fully accounted for by the increased compression ; in every case 
the actual indicated efficiency obtained from the various gas 
engines is a little more than half of that which would be given by 
an ideal air engine following the same cycle in a perfect manner 
without loss of heat to the sides of the cylinder. 

It is interesting to observe that the actual efficiency improves 
somewhat more rapidly with the increase of compression than 
does the thermodynamic advantage due to compression ; that 
is, when the theoretical efficiency is 0*33 the actual experimental 
efficiency is '33 x "51 =-17 : with theory 0*40 the actual efficiency 
is -40 x -53=0-21, while with 0*428 theory the actual is 0*428 x 

•58=**5. 

The proportion of the theoretical efficiency actually obtained 

in practice thus rises from 0*5 1 to 0*58. This means that with 
higher compressions in addition to the thermodynamic advantage 



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378 



The Gas Engine 



due to change of cycle there is also a further advantage due 
to a diminution of proportional loss of heat to the cylinder 
walls. 

From this it follows that very probably great further economies 
are to be obtained by further increase of compression, care being 
taken of course to preserve a properly shaped compression space, 
that is a space having small cooling surfaces in proportion to the 
volume of the compressed charge. Some of the advantage is 
also due to the more rapid conversion of the heat of the explosion 
into mechanical work by reason of the small space through which 



. Z40 




9 

Fig. 177. — Comparative Diagram. 
Crossley Otto Engines with different compressions. 

the piston moves while doing a large part of the total work of its 
stroke. 

To render the effect of compression readily visible to the eye 
the author, has drawn a diagram, fig. 177, in which the length of 
the line a b represents the total capacity of the cylinder including 
the compression space ; c b represent the stroke and a c the com- 
pression space according to a diagram of a test taken by the 
author in 1888, and d ef b is that diagram plotted down on the 
scale of T Is inch equal to one pound. 

The line a g represents the compression space and gb the 
stroke of the Otto engine tested by the Society of Arts, while h i 



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The Present Position of Gas Engine Economy 379 

k b is the diagram taken from the Society of Arts Report of 1888 
plotted down to the same scale as the first diagram. 

The line a I represents the compression space and / b the 
stroke of the engine tested by the author at Messrs. Crossle/s 
works, while m n bis the diagram fig. 135, p. 316, also plotted 
to T ^ in scale. 

The three diagrams are also numbered 1, 2, and 3. It is quite 
evident that No. 2 is larger in area than 1, and that 3 is consider- 
able larger than both. These diagrams show in a clear way the 
great advance made by increasing compression on the indicator 
diagram. Mr. Atkinson considers the improved results obtained 
with the Crossley Atkinson scavenging engine to be due not to 
any increase in compression, but to the displacement of the 
burned gases from the cylinder, and he does not consider that 
increased compression has anything to do with the increased 
economy. These opinions he advanced in a paper read before 
the Manchester Association of Engineers. 

The author has always advocated and believed in scavenging 
a cylinder by means of air, and in many of his engines he has 
entirely discharged the exhaust gases by air forced in by a pump. 
He has never been able, however, to credit such scavenging with 
more than 5 per cent, economy as compared with the same engine 
working at the same compression and retaining the exhaust gases. 

The results of many tests with gas engines of the three cycle 
variety of the Otto type, in which one revolution is devoted to 
replacing the whole of the exhaust gases by air, proves to demon- 
stration that the gas consumption per IHP is not materially 
reduced by the act of displacing the exhaust products. Such 
engines have been constructed by Linford, Griffin, Barker and 
others before the expiry of the Otto master patent, and although 
in them the exhaust products were entirely displaced by air 
they did not show a marked economy. 

The matter, however, may be considered as positively deter- 
mined by the experiments communicated to the author by Mr. A. 
R. Bellamy, and the diagrams given at figs. 139 and 140 showing 
with a compression of 60 lbs. per sq. in. above atmosphere 
a consumption of 19 cb. ft. per IHP hour, and with a com- 
pression of 90 lbs. a consumption of 17*6 cb. ft. per IHP. In 



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380 Tlie Gas Engine 

comparing these figures with the results obtained by the author at 
Messrs. Crossley's works, it is to be remembered that Openshaw 
gas is considerably greater in heating value than the gas used by 
Messrs. Andrew & Co. at Reddish. Mr. Bellamy's diagrams were 
taken from the same engine with two different compression 
chambers successively applied. 

Scavenging by pure air has, however, great practical advantages. 
The average available pressure which can be economically obtained 
in the cylinder is greatly increased, and for really large engines it 
is absolutely necessary to scavenge in order to avoid premature 
explosions. This is especially true when high pressures of com- 
pression are adopted. With such compressions premature ex- 
plosions are caused by the presence of the hot burned gases, 
and when these hot gases are removed by pure air the cold pure 
mixture may be compressed to very high pressures without danger 
of early ignition. The admission of air in the first place also 
prevents any chance of igniting the incoming charge during the 
charging stroke. 

The author therefore considers that Messrs. Crossley & 
Atkinson's new scavenging device is a most valuable invention, 
inasmuch as it permits of clearing out all waste products by a 
device so simple as to add no complications to the engine. It is 
more valuable, however, for large engines than for small ones, as 
it is much more desirable to discharge exhaust products in large 
than in small engines. The invention is especially applicable to 
engines using Dowson gas, and it considerably increases the 
available pressure with such engines, by so increasing the air 
supply present as to enable more gas to be burned economically 
in the cylinder. 

Figs. 178, 179 are diagrams taken from the same * scavenging' 
engine with ordinary gas and Dowson gas. 

The engine has a 17-inch diameter cylinder and 24-inch stroke. 

In fig. 178, the coal gas diagram, the power indicated is 121 
horse, with an average available pressure of 113*5 ^s. per sq. in. 
In fig. 179, the Dowson gas diagram, the very satisfactory avail- 
able pressure of 97*4 lbs. is obtained. 

The engine is rated at 30 HP nominal. 

The Dowson diagram is a great improvement on that obtained 



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The Present Position of Gas Engine Economy 38 1 

with the same gas on a non-scavenging engine ; the highest 
available pressure claimed by Mr. Dowson for an engine this size 
is 82 lbs. per sq. in. 

Even with the scavenging device, however, it does not seem 
safe to rely upon a higher pressure for anything like full load 
than 65 lbs. persq. in. with a 16 HP nominal Crossley Otto. 

Methods still open to obtain increased Economy, — Modification 
may still be made in the indicator diagram of the gas engine to 
further increase efficiency, and the author will now discuss such 
points as appear to him capable of improvement. In doing this 
the author will refer to the Otto cycle, but it is to be remembered 
that the impulse-every-revolution engines may be arranged to 
produce any of the results brought about by the Otto engine. 

The author has pointed out that the actual indicated efficiency 
of a gas engine increases with the theoretic efficiency, and that 
the actual efficiency varies from 0*51 to 0*58 of the theory. The 
actual indicated efficiency also increases with the dimensions of 
the engine, other things being similar, when the ratio of compres- 
sion space, and therefore the theoretical efficiency, remains 
constant. Thus at p. 377 an engine of 9^ ins. cylinder and 18 
in. stroke having a theoretic efficiency of 040 gave a practical 
indicator efficiency of 0*21 or 0*53 of the theory. 

Referring to a careful test, already mentioned, of a 100 HP 
double cylinder Otto engine made in Philadelphia by Mr. 
H. W. Spangler, it will be found that the cylinders were each 14 
in. diameter by 25 in. stroke ; the engine gave as an average 127 
I HP and 9 2 5 brake HP at 160 revolutions per minute. The 
clearance space was practically 28 per cent, of the whole cylinder 
volume, that is 28 per cent, of the volume swept by piston + 
compression space volume. 

The theoretic efficiency of such an engine is 0*41, but the 
actual efficiency was found to be 0^277, so * nat 

0-277 
o^r=°' 6 75 

The actual efficiency, instead of being only 0*58 of the theoretic, 
rises to 675 of it, due to change in the dimensions of the engine 
without practical change in the compression. 

The engine mentioned on page 377 as 7 in. diameter and 



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382 



The Gas Engine 



15 in. stroke gave an efficiency of 0*25, while the larger engine 
of 11 in. diameter cylinder and 21 in. stroke, having a similar 
compression space, gave an efficiency of 0-275. 




Fig. 178. — Diagram, Crossley Otto Engine (coal gas). 





330 
























300 


t\ 


















270 


X 


















240 


\ 


\ 
















210 




\ 














hi 

-I 

< 



160 
ISO 




\ 




HR W4LM. 












ito 

00 


M 


2 


« 

N 


5^ 




s 


3 


$ 


* 


% 




•0 
























30 . 















































Fig. 179.— Diagram, Crossley Otto Engine (Dowson gas). 

The theoretical efficiency in both cases is 0428, and the 
ratios are : 

The actual efficiency, therefore, increases with the dimensions of 
the engine, the compression remaining constant. 



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The Present Position of Gas Engine Economy 383 



Comparison of the Actual and Theoretic Efficiencies 
of Otto Engines of different Dimensions. 



Engine cylinder 



Relative Theoretic ' : n ^?L 
'capacity efficiency ■££* 



Nearly equal] 7" diam ' x '5" stroke. 

compression \ ... .. 

v 114" diam. x 21" stroke 

Nearly equal I *" diam - * l8 " stroke 
compression \ „ ,. 

1 14" diam. x 25" stroke 



I 



1 

377 

1 
297 



'428 
'428 
•40 
# 4i 



•25 
•275 

'21 



Ratio of ac- 
tual and ideal | 
efficiency j 



_?S = 
'428 
■275 = 
•428 
•21 



•58 
64 



= '53 ! 



•41 

277 I ;»zz.-67 

"4 1 



From these numbers it is evident that efficiency for equal com- 
pression increases considerably with the dimensions of the engine. 

There is, however, a limit to this increase of efficiency with 
increased dimensions. 

The increase in the efficiency of the larger engines as compared 
with the smaller using the same proportion of compression space 
is due to the diminished proportional loss of heat from the gases 
of the explosion to the inclosing metal walls, and it is always found 
that in larger engines the expansion curve tends more and more 
to rise above the adiabatic line. With a maximum temperature 
of explosion of about 1600 C it is found by experiment that 
the actual increase of temperature due to explosion accounts for 
about from 06 to 07 of the total heat of the gas present ; there 
is therefore heat enough present in a gas engine of ordinary 
proportions, if none be lost, to keep up the temperature during 
expansion performing work to the maximum 1600 during the 
whole expansion stroke. The increase in dimension if carried 
to an extreme could therefore only reduce the loss to insignificant 
relative proportions, and in such a case the mass of incandescent 
gas might be considered to lose no heat whatever to the walls of 
the cylinder. 

Assume an air engine in such a case ; the total volume of 
the stroke plus clearance space being 1 cb. ft. 

Assume the engine to have a compression space of 0*275 °f 
the whole cylinder volume, as in the test made by the author on 
Crossle/s Otto scavenging engine, page 316. Then the diagram 



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384 



The Gas Engine 



and results would be as shown in fig. i8o, where the temperature 
of explosion is 1600 C. 

From this it will be seen that while 0-409 is the efficiency 
for adiabatic expansion, then 0*346 is the efficiency for isothermal 
expansion ; from this, then, it appears that, allowing for the known 
property of the suppression of heat in a gaseous explosion, the 



360 




► ---0-38VO!--*--!*- 10 You. .*.-.- h 



Efficiency of adiabatic compression and expansion =0*409. 
Efficiency of adiabatic compression and isothermal expansion =0*346. 

Fig. 180.— Theoretical Diagram, 
comparing adiabatic and isothermal expansion. 

utmost efficiency possible for an engine using coal gas, having 
a compression space of 0*275 °f tne tota l cylinder volume, and 
expanding to the same volume as existed before compression, 
is 0*346, so that the efficiency actually attained in practice is 

2 ';=o-8o or 80 per cent, of the possible. 
•348 

So far, then, practice has shown that the absolute efficiency of 

the gas engine has been increased from 17 per cent in 1882 to 

practically 28 per cent, in 1895, that is from converting 17 percent 

of the whole heat into indicated work to 28 per cent, of the whole 



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The Present Position of Gas Engine Economy 385 

heat, and this great change in economy has been brought about 
by increase in compression alone. The compression pressure 
has risen from 35 lbs. per sq. in. above atmosphere to 90 lbs. 
per sq. in. 

The question now arises, How far can this compression be still 
enhanced? It will be observed from the formula 10 on page 
53 that the efficiency increases somewhat slowly at the higher 
pressures, and thus a limit must be reached beyond which the 
increasing weight and dimensions of the engine parts due to rising 
maximum pressure will more than compensate for the improved 
theoretical economy. 

Assume, for example, that a compression of 210 lbs. per sq. in. 
above atmosphere is feasible ; the volume of the compression 
space will then be 0*144 of the total cylinder volume, so that the 
theoretic efficiency of such an engine will be 



-<-ur* -*. 



The ideal efficiencies for different compressions thus stand : 

E=o*33 for 38 lbs. per sq. in. compression above atmosphere. 
E=o - 40 ,, 66*6 ,, ,, ,, ,, ,, 

E«=o*428 „ 87*5 ,, 

E-O'546 ,, 2ZO ,, ,, ,, ,, ,. 

Such a compression as 210 lbs. per sq. in. above atmosphere 
would produce with an explosion temperature of 1600 C. 
a maximum pressure of 675 lbs. per sq. in. above atmosphere, 
and this would involve an engine of nearly double the weight 
of working parts as compared with the engine tested by the 
author at Messrs. Crossley's, with but a small increase in power 
for the great increase in weight. 

The author accordingly considers a compression of 200 lbs. 
per sq. in. as considerably above the limit likely to be useful 
in a simple gas engine ; to render such compressions possible 
he considers that compound engines will require to be designed. 

The gas engine, in the authors opinion, is now rapidly nearing 
the limit of advantageous increased compression, so that no 
great further economy is to be expected there. 

Looking at diagram 3, fig. 177, however, it will be observed that 

c c 



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386 TJie Gas Engine 

at the moment of opening the exhaust valve there is still in the 
cylinder a pressure of about 50 per sq. in. above atmosphere. 
It is obvious that if the cylinder of that engine had been longer 
and the piston could expand farther, the pressure could have 
been reduced while the expanding gases were performing work in 
it This source of economy has long been obvious to engineers, 
and many have attempted to realise it in practice. The author 
has calculated an ideal case of this kind in which the pressure of 
compression was 100 lbs. per sq. in. above atmosphere, the 
explosion temperature 1600 , and the (adiabatic) expansion carried 
on far enough for the contents of the cylinder to fall to atmo- 
spheric pressure. The theoretic efficiency of such an engine 
would be 055, and with an engine of about 200 IHP a practical 
efficiency of 0*55 x 6 = -33 is probable. 

In the author's opinion efficiencies of 35 per cent of the 
whole heat given to the engine are now within the reach of the 
engineer. 

The question, however, as to whether greater or less expansion 
should be utilised in an engine is altogether a matter of dimen- 
sions ; for small engines great expansion beyond the volume of 
the charge before compression is inadvisable, as the reduction of 
the volume of mixture dealt with at each stroke may readily so far 
increase the relative loss of heat to the cylinder as to more than 
neutralise the gain obtained from the extra expansion. 

In very large gas engines it will be undoubtedly advisable 
to adopt the compound principle, and many engineers have 
attempted compounding; so far, however, compounding is not 
successful. Otto, Clerk, Atkinson, Crossley, Burt, Dick, Kerr & 
Co. and others have attempted compounding, but the principles 
involved are not yet thoroughly understood and require further 
investigation. 

One important point, however, is clearly established by Burt's 
engine, figs. 156, 157, and 158, that flame gases do not lose much 
heat when passed from cylinder to cylinder by short open ports. 
Experiments made by the author also bear this out Compound- 
ing to be successful must be carried out by means of very short 
straight and unobstructed ports. 



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PART III. 
OIL ENGINES. 

CHAPTER I. 

PETROLEUM AND PARAFFIN OILS. 

Oil engines .resemble gas engines in this, that the power is gene- 
rated by the explosion of a compressed inflammable gaseous 
mixture in an engine operating according to the well-known Otto 
cycle. 

In the older gas engine patents it was customary to assume 
that a gas engine was necessarily an oil engine also, and that only 
trifling additions or modifications were required in order to con- 
vert any gas engine into an oil or inflammable vapour engine. 

For many years, however, the difficulty of using safe oil and 
producing compressed explosive mixtures from it was so great that 
no effective oil engine was placed upon the market. Even now 
the oil engine is a much more tricky machine than the gas engine, 
although it is more reliable than was formerly the case, and it is 
rapidly settling down by the industry and experiments of many 
inventors to something like a standard type. 

In the earlier oil engines very light inflammable oils of the 
gasoline kind were used to supply the engine with inflammable 
vapour, and in these the problem of vaporising the oil was com- 
paratively simple. It was only necessary to draw air over a surface 
saturated with gasoline or some lighter oil, to produce a mixture 
of inflammable vapour and air, which when taken into the cylinder 
of a gas engine readily supplied the place of the ordinary coal 
gas, and gave explosions under compression closely resembling 
those obtained with coal gas* The legal restrictions placed upon 



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388 Oil Engines 

the carriage and storage of such light oils, however, made it 
impossible for engines using only such oils to be applied exten- 
sively in this country, and accordingly it became necessary to 
devise engines with vaporisers of a kind capable of supplying 
inflammable vapours of gases to an engine using oil such as is 
commonly adopted for petroleum or paraffin lamps. Such oils are 
much less volatile than the gasoline oils already mentioned, and 
accordingly it is much more difficult to produce from them 
inflammable vapours capable of exploding in a gas engine 
cylinder. 

The object of the engineer in dealing with those heavier oils 
is to so treat them as to charge the engine cylinder with an 
inflammable mixture of air, and the particular hydrocarbon, which 
mixture is sufficiently stable in the gaseous or vapour state to stand 
compression without liquefaction. At the same time the explosion 
obtained should be powerful and regular, and the combustion so 
complete as to avoid deposits capable of clogging the valves and 
working parts. 

Many difficulties have been found in so vaporising oils as to 
produce a suitable inflammable mixture, and at the same time 
avoid clogging up the vaporiser or the engine. 

A knowledge of the properties of the principal hydrocarbons 
used will assist the engineer in deciding between differing methods 
of procedure, and accordingly the author will now describe and 
discuss the properties of the various hydrocarbon oils from the 
point of view of the oil engine inventor or designer. 

Chemistry of Petroleum and Paraffin Oils. — A few words will 
first be necessary, however, on the chemistry of petroleum and 
paraffin. The oils used for petroleum engine purposes consist 
mainly of three varieties — American petroleum, Russian petroleum, 
and Scotch paraffin oil. 

The American and Russian petroleum is obtained by refining 
crude oil which issues from oil wells found in the United States 
of America, and in Russia on the shores of the Caspian Sea. 

Crude petroleum, as it issues from the wells, is a mixture of 
many different substances, some gaseous, some liquid, and some 
solid ; the crude petroleum is, in fact, a liquid containing various 
gases in solution, and various solid bodies as well. The various 



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Petroleum and Paraffin Oils 389 

liquids, solids and gases, however, resemble each other in one 
particular. They are every one of them hydrocarbons, that is 
chemical compounds of which hydrogen and carbon are the sole 
constituents. 

American petroleum consists principally of hydrocarbons be- 
longing to a chemical series known as the paraffin series. This 
series has the general formula C n H 2n+2 . Members of another 
chemical series, however, are mixed with the paraffin group. 
This other series is known as the olefine series, and the general 
formula is C n H 2n . 

Both the paraffin and the olefine series comprise substances 
ranging from the gaseous state to the solid state ; that is, each series 
contains substances which are solid, substances which are liquid, 
and substances which are gaseous. 

The lightest member of the paraffin series is the well-known 
marsh gas methane (CH 4 ), and one of the heaviest of the liquid 
products is known as pentadecane, C 1S H 32 , and the solid paraffin 
so well known in commerce in the form of paraffin candles is a 
mixture consisting principally of solid members of the paraffin series, 
together with some solid members of the olefine series. The 
olefine series likewise comprises a whole range of compounds 
beginning with the well-known gas ethylene (defiant gas), and 
terminating with solid olefines containing more than 20 equi- 
valents of carbon to 40 equivalents of hydrogen. 

Crude Pennsylvania petroleum as it issues from the wells 
gives off as gases : 

Methane (Marsh Gas) C H 4 

Ethane C 2 H a 

Propane C 3 H 8 

and 12 separate hydrocarbons of the paraffin series have been 
isolated from the crude liquid. These twelve hydrocarbons are 
given in the table on page 390 with formulae, specific gravity, and 
boiling point of each. 

All these hydrocarbons, except the first, are liquid at ordinary 
temperatures. The boiling points of the hydrocarbons vary from 
o° C. to 260 C, and the specific gravity from -65 to 792. 

It will be observed that in every one of these compounds, the 
hydrogen atoms going to form the molecule are double the 



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390 



Oil Engines 



number of the carbon atoms, plus an additional two hydrogen 
atoms. Marsh gas, for example, has in the molecule i atom car- 
bon, and 2 atoms hydrogen + 2. Ethane has 2 atoms carbon, 
and 4 atoms hydrogen + 2, that is 6. The same proportion is 
given in all the members of the series in the table. 

Some Hydrocarbons of the Paraffin Series 
found in Pennsylvania Petroleum. (Redwood.) 



Name 



Butane . 
Pentnne 
Hexane . 
Heptane 
Octane . 



Nonane . 

Decane . 

Endecane 

Dodecane 

Tridecane 

Tetradecane 

Pentadecane 



Formula 



C 4 H 10 
C 5 H l2 
C 6 H l4 
C 7 H 16 



1 1 . I! 

1 ,,13., 

CngM 

C|fjH w 

C U H*» 
C U H« 



Specific Gravity 


Normal 


0645 at o° C. 


0-645 . 


, o°C. 


063 , 


. 17° C. 


0712 , 


, 16 C. 


0726 




071 at 1 5 C. 


0757 . 


. 15 c. 


0765 . 


. 16 C. 


0766 , 


, 20°C. 


0792 . 


, 20° C. 



Boiling Point 



Normal 
o°C. 

38° c. 
t 9 °C. 
9 8 J C 
i24°C. 



I so. 

3o°C. 
6i°C. 
9i°C. 
118 C. 



Boiling Point 
136 to 138 C. 



l6o c 
i8o°„ 
196°., 
216 „ 

236 „ 

255° .. 



162 C. 
i8 4 °C 

200°C. 

218 C. 
240°C. 
26o°C. 



Pentadecane, the highest here shown, has 15 atoms carbon 
associated with 30+2 atoms of hydrogen. 

The hydrocarbons of this series resemble each other very 
much in chemical and physical properties. They decompose 
under the action of heat in a similar manner, and they have 
similar physical properties. Chemists call such a series of com- 
pounds a homologous series. 

The American refined lamp oils of commerce consist prin- 
cipally of the heavier hydrocarbons given in the list, but they also 
contain in smaller quantity hydrocarbons of the olefine series. 

The table on page 391 gives a few of the best known mem- 
bers of this series. 

These compounds form what chemists call an isomeric series, 
because, as will be observed, they are all of the same percentage 
composition. Each hydrocarbon of the series contains exactly 
the same proportion of hydrogen and carbon, namely, 857 carbon 
to 14*3 hydrogen. The compounds, however, differ in molecular 
density, and this is found by the increasing vapour density ; 



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391 



thus, if one volume of ethylene be taken as the unit of weight, 
an equal volume of butylene weighs 2, hexylene 3, and so on. 

Some Members Of the Olefin e Series. 











Boiling Point 


Specific Gravity 


Ethylene (Oiefiant Gas) . . C 2 H 4 


Gaseous 




Propylene 


. C 5 H 6 . 


,, 




Butylene . 






. C 4 H 8 


4°C. 




Amylene . 






. C 5 H 10 


73° C. 




Hexylene . 






C 6 H 13 


. 70 C. 




Heptylene 






• QH M 


84 C. . 


. 0714 at o° C. 


Octylene . 






. C 8 H 16 


. 119 c. 




Diamylene 






• ^10^20 • 


165° c. . 


. 0777 at o° C. 


Tri amylene 






• CisHso . 


248°C. 




Tetramylene 






. CayH*) . above 390 C. 





The term isomer is sometimes limited to compounds of the 
same molecular density as well as the same percentage composi- 
tion. Such compounds, however, differ in physical and chemical 
properties. 

At first it is very surprising to find that two chemical substances 
of identical chemical composition and molecular density, that is, 
with the exact proportions of the element present, the same in 
both, should have different properties, but the case is strictly 
analogous to what is known of the elements. Many chemical 
elements are known to exist in several forms, without change of 
chemical composition. Carbon exists, for example, in three forms, 
the diamond, graphite, and charcoal. These three forms are 
widely different in appearance and physical properties, but each 
contains nothing but carbon, and produces nothing but carbonic 
acid on burning. 

Phosphorus also exists in two forms, yellow and red, and it 
is more than suspected that iron exists in several forms. 

When elements vary in this way, the variations from the best 
known form are called allotropes or allotrofie modifications. 
When a chemical compound has several varieties, the variations 
are known as isomers. The word isomer, however, is more strictly 
used to denote compounds not only of the same percentage 
composition, but of the same molecular weight. 

Bodies of the same percentage composition and different 



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392 Oil Engines 

molecular weights are known as polymers. The olefine series 
then are polymers. 

The defines are present in American petroleum to only a 
small extent, but in Russian petroleum they form the principal 
constituents. The hydrocarbons present in Russian petroleum 
are not quite the same as the normal olefines, but appear to be 
isomeric modifications of the true olefine series, having the 
general form of C n H 2n _ 6 H 6 . This formula seems to be a round- 
about way of expressing the same thing as C n H 5n , because 6H is 
deducted, and 6H added. It is not, however, the same form as 
C n H 2m but expresses chemical relationship to another set of com- 
pounds. The compounds of the general form CnHjn^Hg are 
called naphthenes, and the naphthenes, although of the same per- 
centage composition as the olefines, resemble the paraffins more 
closely in their chemical decompositions. The naphthenes, which 
have been isolated from Russian petroleums, are according to 
Redmond as follows : 

Naphthenes isolated from Russian Petroleum. 
C 8 H 16 . . . 119 C. C 12 H 24 . . . i96°C. 

C 9 H 18 . . . i 3 6°C. C M H, 8 . . . 24o°C 

C 10 H2o . . • i6i°C. QjHso . . . 247 C 

CuHaa . . . i8o° C. 

The specific gravity of the first-mentioned hydrocarbon 
octonaphthene, C 8 H l6 , at o° C. is 7714, and that of dodeca- 
naphthene at 17 C. is -8027. 

Paraffin oil, as its name implies, is mostly composed of 
members of the paraffin series, and it is produced by the destruc- 
tive distillation of Scottish shale. The crude oil obtained from 
the retorts contains, like petroleum, substances both solid, liquid, 
and gaseous. The solid paraffin of commerce is generally obtained 
irom this paraffin oil. 

The chemistry of petroleum and paraffin oils is extremely 
complex, and only a general idea has been here given of the main 
constituents. 

Before leaving the chemistry, it is desirable to consider the 
decompositions of these compounds by heat. It is found, for 
example, that if a heavy member of the paraffin series be exposed 
to heat under pressure, so as to attain a temperature higher than 



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Petroleum and Paraffin Oils 



393 



the boiling point, then that compound decomposes into a lower 
paraffin and an define. The paraffin hydrocarbon Ci 2 H 26 , for 
example, may be decomposed into hexylene C 6 H 12 , and hexane 
C 6 H 14 . The reaction may be taken as follows : 

C l2 H 26 =C 6 H 1 2 + C 6 H l 4. 

The heavier hydrocarbon thus splits up into a paraffin and an 
ethylene containing a smaller number of carbon and hydrogen 
equivalents to the molecule. It depends entirely, however, on 
the particular temperature and treatment as to the actual decom- 
position which will take place. If the temperature of the hydro- 
carbon be raised to a high enough point, marsh gas, CH 4 , can be 
produced, and carbon left in the retort. The olefines decompose 
also, heavier olefines producing lighter olefines by the influence 
of heat, or lighter olefines together with hydrogen, marsh gas, and 
solid carbon deposit 

Petroleum Ether and Spirit — The volatile liquids produced 
from American petroleum have been classed as petroleum ether 
and petroleum spirit. The following table gives a list of the 
substances so produced. The names given are not chemical 
names, but ordinary trade names, and the compounds are not 
pure hydrocarbons of one composition, but mixtures of hydro- 
carbons boiling at very low points. 

Petroleum Ether and Spirit. 



Petroleum Ether 



Petroleum Spirit 



• I* 



Cymogene .... 
Rhizoline .... 
Gasoline .... 
C Naphtha (Benzine Naphtha) 
B Naphtha 
A Naphtha (Benzine) . 



Specific Gravity 



•590 
•625 to "631 
■635,, -666 
'678 ,, 700 
7i4». 7i8 
74i .. 745 



According to Mr. Alfred H. Allen, cymogene consists chiefly 
of butane, C,H, , of pentane, C 5 H 15 , and an isomer of that 
substance ; and hexylene, C 6 H l? , and an isomer of hexylene. 

As these products are extremely volatile, cymogene boiling at 
o° C, the freezing point of water, and the heaviest A naphtha 
boiling away under 70 C, it follows that they are dangerous to 
handle, and are far too inflammable for general use in oil engines. 



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394 Oil Engines 

The substance cymogene, for example, could only be retained in 
the liquid state permanently by means of a freezing mixture, and 
all the others are so volatile that it would be dangerous to 
approach an open vessel containing them with a light. Any one 
of these liquids would go on fire instantaneously on plunging a 
lighted match or taper into the liquid. Liquid so inflammable 
and so capable of producing large volumes of explosive mixture 
are much too dangerous for successful use by the general public 
in engines. 

The whole of these liquids are clear limpid fluids, having 
when pure a rather agreeable odour. 

Petroleum and Paraffin burning Oils sold in Britain. — The 
oils which really concern the engineer designing petroleum 
engines are not the crude oils or the petroleum spirit or ether, 
but the burning oils which are sold in Britain in a condition 
sufficiently safe to be used in ordinary lamps. The Petroleum 
Act of 1876, and its subsequent modification in 1879, determines, 
that oils sold for illuminating purposes shall not have a flashing 
point less than 73 F., the flashing point to be determined by a 
special apparatus fully described in the Act. The apparatus and 
the method of manipulating it are the work of Sir Frederic 
Abel, so that the standard test for these oils for flashing point is 
known as the Abel test. 

Fig. 181 is a section of the Abel close test apparatus, from 
which it will be seen that a copper vessel c is provided which 
contains water marked w. This water forms a water bath. An 
air chamber a is placed within the water bath, and it carries 
within it an oil cup p made of gun metal. This cup rests upon an 
ebonite ring, and over the air chamber a, and has a tight-fitting lid 
on which is fixed a gas burner. The oil cup carries a thermo- 
meter /, and above the cover is fixed a slide, which slide on 
being moved is caused to uncover three holes. The gas jet 
swivelling on a lever, and moving with the movement of the 
slide, carries a small flame, and the movement is so combined 
that, as the lever tilts, the flame is passed through one of the 
openings in the slide and reaches the top of the oil in the oil 
cup. 

The thermometer f is intended to take the temperature of the 



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Petroleum and Paraffin Oils 



395 



water bath, and the spirit lamp b supplies the necessary heat 
The pendulum shown alongside of the apparatus is 24 inches 
long, and is intended to time the operation of testing the flash. 

To determine the flashing point of the oil, the temperature of 
the water bath at the start of the test is arranged at exactly 130 F. 
The oil to be tested is cooled to 6o° F. and poured carefully into 
the oil cup p, avoiding splashing, until the oil reaches the point of 
a small bent wire gauge inside the cup. The lid is then put on, 
and the cup placed in the bath, the rise of the temperature being 




Fig. 181.— Abel Flash Test Apparatus. 

watched on the thermometer / in the petroleum cup. When the 
oil reaches the temperature of 66° F. the testing is started by 
setting the pendulum in motion, and while it makes three oscilla- 
tions, drawing the slide slowly open, and at the fourth oscillation 
closing it rapidly. By this the test flame is gently tilted through 
a hole in the slide to the space above the oil. This operation is 
repeated once for every increase of temperature of i° F. until the 
vapour of the oil ignites within the oil cup, giving a pale blue 
flicker or flash. The temperature of the oil at which this occurs 
is called the flashing point ; that is, the flashing point is that 



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396 Oil Engines 

temperature at which the oil gives off sufficient vapour to be 
ignited by a flame. The lowest flashing point allowed by law for 
petroleum intended for burning lamps in this country is 73 F. or 
22*8° C. It is very important, therefore, in experimenting upon 
various samples of oil, to make certain that the oil is above the 
legal flashing point. 

Other qualities are also necessary, and these can be determined 
by the specific gravity of the oil, and by the distillation of the oil, 
and observation as to the range of temperature during which the 
oil boils over. 

The ordinary burning oils sold in Britain are American oils, 
Royal Daylight, Ordinary, Water White, and Tea Rose. 

The Russian oils are Russoline and Russian Lustre. 

The paraffin oils are Broxbourne Lighthouse, Young's paraffin 
oil, and similar oils by many other makers. 

Professor Robinson has made an interesting series of experi- 
ments upon the principal burning oils sold in Britain, and he has 
determined the specific gravity flashing point by Abel's test, the 
point at which each oil begins to boil, and the percentage distilled 
between certain ranges of temperature. He has also made deter- 
minations of the specific heat, and the co-efficients of expansions 
of several of the oils. 

The opposite table gives a summary of his results. 

From this table it will be seen that the burning oil with the 
lowest flashing point is American Ordinary, which has a light straw 
colour, a specific gravity of 791, and was sold some time ago at 
$\d. per gallon. This oil begins to boil at 145 C. ; at 215 C 
29 per cent, of the oil distils over to the condenser ; and at 233 C. 
36 per cent, distils. To vaporise the entire oil, therefore, required 
a temperature above 233 C. 

Looking at the table, Royal Daylight oil begins to boil at 144 
C. ; and when the thermometer reaches 215 C. 25 per cent, of the 
liquid is distilled. At 230 C. 35 per cent, is distilled. At 300 C. 
Professor Robinson states in another part of his paper that 76 
per cent, boils over, and at 340 C. 82 per cent. At 358 C, the 
extreme limit of the thermometer used, there was still a consider- 
able residue. The Royal Daylight oil, therefore, contains a very 
wide range of hydrocarbons, beginning probably with octane, 



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± 
a 



| co co ^ co CO 



I 



%% B ft % I 38>8 



I 

Q 






83 »# 3 
5.a § J? .sr 



Uo fl « O M coo o 

jh s n i cT^i, 



!» 9 K S ft I I 
I 2 



CO M lO 



o o o o 



*■ io o o m »o 

. 4- *• i/> m ir> I \o 

W>M H M H H I H 




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398 Oil Engines 

CgHig, and certainly containing towards the end higher hydro- 
carbons than pentadecane, C, 5 H 32 . 

Another American burning oil, Water White, having a specific 
gravity of 78, has a flashing point of 108 F., begins to boil at 
150 C, and at 2 1 5 C. 55 per cent boils off. 

This oil is evidently of simpler composition than the others ; 
that is, it contains hydrocarbons within a smaller range of mole- 
cular weight. 

Russoline, it will be observed, the Russian ordinary burning 
oil, begins to boil at 15 1° C, and by the time the temperature has 
reached 22 1°, only 36 per cent, has boiled over. The flashing 
point, therefore, of this oil is high, 82 . 

Broxbourne Lighthouse oil begins to boil at about 215 , and is 
completely boiled over at 300 . 

From these experiments it appears that many of the burning 
oils of commerce are so constituted that even at so high a tem- 
perature as 350 C, part of the oil refuses to come over. 

It is quite evident that the type of vaporisers required in a given 
case must be largely determined by the nature of the oil. Thus an 
engineer working with Broxbourne Lighthouse oil would find that 
he succeeded in evaporating the whole of the oil at 300 C. by the 
agency of heat alone, whereas if he had experimented with Ameri- 
can Ordinary oil, he would have found at that temperature a very 
large residue remaining in his vaporiser. 

Methods of Vaporising and Decomposing. — Before discussing 
the vaporisers in actual use, it is advisable to consider some of 
the laboratory methods of vaporising, in view of the difficulty of 
providing vaporisers which will treat varying oils of high flashing 
point and density. 

When a homogeneous substance like water is boiled, the tem- 
perature remains constant from the moment of boiling to the com- 
plete distillation of the whole liquid. 

Likewise if dry air be blown through water, every cubic foot of 
air will carry off a certain volume of water vapour, until the whole 
of the water is evaporated, and this will occur by blowing through 
air at any temperature at which water has an appreciable vapour 
tension. 

The vapour tension of water is the pressure of water vapour at 



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Petroleum and Paraffin Oils 



399 



any given temperature. The term vapour tension is generally used 
for pressures under atmospheric pressure. 

The following table gives the vapour tension of water for 
different temperatures from o° C. to ioo° C. The tension is given 
in millimetres mercury ; that is, the tension of the water vapour at 
each temperature is given in the height of mercury column which 
the particular pressure of water vapour at that temperature is cap- 
able of supporting. 

Vapour Tension of Water Vapour. 





Tension 




Tension . 


Temp. C. 


mm. Mercury 


Temp. C. 


mm. Mercury 


. . 4'6 


40° . 


• 5491 


5° 


• 5*53 


50° . 


• 9198 


IO° 


• 917 


60^ . 


. 14870 


15° 


1270 


70 . 


. 23309 


20° 


• 17*39 


8o° . 


. 28851 


*5° 


• *3*55 


9o° . 


• 525*45 


3o° 


• 3i'55 


IOO° . 


. 760*00 



From this table it will be observed that at 15 C, about the 
ordinary temperature of the atmosphere, the tension or pressure of 
water vapour is equal to 127 mm. mercury. The total pressure 
of the atmosphere is taken as 760 mm. mercury, from which it 
would appear that the pressure of water vapour at that temperature 
is about 6 V of the pressure of the atmosphere, so that if water were 
to be evaporated by passing air through it at that temperature, 
60 cb. ft would require to be passed through to take away r cb. ft. 
of water vapour, that is to take away a volume of vapour sufficient 
to make 1 cb. ft. of steam supposed to be at atmospheric pressure 
and temperature. If, however, the temperature be raised to about 
8o° C, 2 cb. ft. of dry air would carry away about 1 cb. ft. of steam 
calculated at atmospheric pressure. 

Water can thus be evaporated either by boiling it off by raising 
the temperature above the boiling point, or by passing air through 
it or any other gas at a temperature below the boiling point ; and 
the amount carried off by a cubic foot of air depends upon the 
temperature of the water. 

The important point to remember is, that to however low a 
temperature the water be reduced, it can be entirely evaporated 
by treatment with a sufficient volume of air. 



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400 Oil Engines 

Petroleum or oil in the same way can be evaporated either by 
boiling off, or by treatment with air or gas ; and the temperature 
at which the whole liquid can be evaporated is much reduced by 
passing hot air over the liquid, instead of attempting to boil the 
liquid away. Thus many of the American oils, which leave a con- 
siderable residue at 35 8° C, could easily be evaporated bypassing 
hot air through the liquid, without requiring any further rise of 
temperature. It is often objectionable to attempt to vaporise by 
boiling off or distilling, because in many oils the boiling point is 
so high that the decomposition point is reached before the liquid 
will boil. In such a case, attempting to force vaporisation or dis- 
tillation by increasing the heat only results in the chemical decom- 
position of the oil, and leaving in the vaporiser a comparatively 
large quantity of carbon or tar. A sample, for example, of solid 
paraffin, such as is used for candles, could not be entirely distilled 
by any attempt at boiling ; but if the sample be placed in a vessel, 
which vessel is heated to the highest temperature which the paraffin 
will stand without decomposition on a sand bath — say about 
400 C. — and super-heated steam be blown through the liquid 
paraffin, then nearly the whole of that solid paraffin can be distilled 
without decomposition. From this it follows that, if vaporisation 
is desired without decomposition, the temperature can be kept 
much lower by heating the vaporiser to a predetermined point, 
and then passing hot air over the liquid contained in it. 

It is interesting to note, in connection with the decomposition 
of paraffin and olefines by heat, that mere heating up in a closed 
vessel does not produce any large amount of decomposition. If, 
however, the oil or paraffin be heated up under pressure in such 
manner that the ordinary boiling point is considerably exceeded, 
and that oil be distilled and condensed in a condenser — also 
under pressure— then the oil rapidly decomposes. 

Some well-known laboratory methods of experimenting illus- 
trate in a vivid manner the various facts which are useful to the 
engineer designing oil engines. The distillation of water, for 
example, in the laboratory apparatus shown in fig. 182, and the 
subsequent distillation of oils in the same apparatus, enables one 
to realise the difference between the nature of oils and water. 

The apparatus is very simple, and consists of a glass flask a 



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Petroleum and Paraffin Oils 



401 



having a tightly fitting cork a, through which passes a glass T piece 
by carrying the thermometer b. The free end of the T piece slips 
into the glass condenser tube c. This condenser tube passes 
within a water jacket tube d, fed with a current of cold water by 
the side tube c, which current discharges at d. The condenser 
tube terminates in the glass receiving flask e, supported upon a 
retort stand ; the condenser is held by a clamp, also supported on 
a retort stand, and the distilling flask rests upon wire gauze sup- 
ported on a tripod, and is heated by a Bunsen flame. 

It is an interesting exercise to rig up this apparatus, and distil 
fresh water from the flask, observing the thermometer during the 




Fig. 182.— Distillation of Water. 

process. Fresh water will boil away to the last drop, and collect 
in the receiving flask while the thermometer remains steady at 
ioo° C. from the beginning of the boiling to the completion of 
the distillation. 

If a sample of Royal Daylight oil be placed in the distilling 
flask (carefully dried from water), it will be found that the oil 
begins to boil about 144 C, and that a lighter oil first passes over, 
and that the thermometer slowly rises, so that at 340 C. only 
82 per cent, of the whole had distilled over, and even at 358 C. 
a considerable liquid residue was left in the vessel. If the receiving 
flask be frequently changed in the course of the distillation, oils 
of different densities will be collected, the lighter oils boiling off 

n r> 



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402 



Oil Engines 



first, and the heavier in order later. Such a process of distillation 
is called fractional distillation, and on the manufacturing scale it 
is practised to purify the oils, and separate the light from the 
heavy. In making this experiment with oil, the apparatus should 
be modified as shown in fig. 183, where the wire gauze is replaced 
by a sand bath, in order to protect the glass flask containing oil 
from the direct action of the flame. In distilling oils experimentally 
from glass flasks, it is well to limit the size of the flask not to 
exceed 250 c.c. (quarter litre) ; and a quantity of dry sand should 
be kept at hand to extinguish the oil flame if the flask breaks and 
ignites. 




Fig. 183. -Distillation of Oil. 



It is found that as the lighter oils distil off and the thermo- 
meter rises, the oil in the distilling flask gradually becomes darker 
in colour, and at the high temperature of 350 C. it becomes quite 
brown. At first it is of a pale straw colour, and this change to 
brown proves chemical decomposition to be going on. 

If a quantity of the oil which refuses to boil at even the high 
temperature of 350 C. be placed in one end of a bent glass tube, 
c, fig. 184, and the tube sealed up by the blowpipe flame, then 
the liquid distilled from the end a into the end b without apply- 
ing any cooling, but after distilling returned again to the end a 



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403 



and distilled to b again ; the process being repeated say for 
about twelve times ; it will then be found on opening the glass 
tube that the oil subjected to this distillation under pressure has 
changed its nature very considerably. This can easily be proved 
by returning it to the flask a, fig. 183, and testing the boiling 
point. It is then found that the liquid which before refused to 
boil at 358 C. will now begin to boil below 140 C. and the greater 
part of it will distil over long before 300 C. is reached. 

A sample of the same heavy oil remaining from the first oil 
experiment if placed in a straight sealed tube as a, fig. 185, may 




Fig. 184.— Decomposition of heavy Oil. 

be heated and cooled to the same extent as and for the same time 
as with the bent tube in fig. 184, and after these series of heatings 
and coolings it will be found to have hardly changed its composi- 
tion. These oils if merely heated under pressure without distilla- 
tion can bear comparatively high temperatures without decomposi- 
tion, but if distilled at the high temperature decomposition 
results. 

This appears due to the recombination of the oils when heated 
to a high temperature and cooled slowly. For effective decom- 
position it is necessary to distil. 

The American petroleum refiners treat the heavy oil left in the 

D d 2 



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Oil Engines 



still after distilling off the light and the burning oils by a process 
called cracking. The still is formed with a very large and roomy 
head which causes the oil to condense and run back to the still, 
and in this way after heating for a considerable time it is found that 
the oil is cracked and oils of lower boiling point produced. The 
cracking process, however, is attended with the separation of a 
proportion of solid carbon. 

Professors Boverton Redwood and Dewar have devised a 

method of distilling oils in 
a compressed gaseous atmo- 
sphere which appears to pro- 
duce more rapid and perfect 
decomposition from heavier to 
lighter oils. 

If the thermometer be 
removed from the distilling 
flask, fig. 183, before the 
temperature rises so high as 
to damage it, and the heat be 
further raised, it is found that 
after a time a tarry mass is left 
in the flask which cannot be 
removed by heating. These 
experiments very clearly show 
that the particular oil could 
not be vaporised by boiling off 
without leaving a considerable 
residue. It would, therefore, 
be hopeless with this oil to 
design a vaporiser to boil off the oil as vapour, it would only result 
in the vaporiser being choked with tar and carbon deposit in a few 
hours. 

Some method is required which will vaporise the whole of 
this heterogeneous oil, the heavy part as well as the light. This 
can be done in another way by means of the apparatus shown in 
fig. 186, which is the same as that shown in fig. 183 except that the 
flask a has a wider neck, and the cork carries in addition to the 
T piece and thermometer the air tube d. If the flask a be 




Fig 185.— Heating heavy Oil 
in a straight tube. 



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405 



charged with Daylight oil and heated up to about 140 , then air 
be slowly bubbled through the oil (from a gasometer), it will 
be found that the whole of the oil can be distilled out of the 
flask a without leaving any heavy residue, and the temperature of 
the thermometer need not be raised above 200 C. In this case 
almost the whole of the contents of the flask will pass over with- 
out decomposition and without leaving any clogging residue or 
carrying over any tarry matter. 

If a sample of solid paraffin be placed in the flask fig, 186 and 
heated up to about 350 , then dry steam be blown through by the 




Fig. 186. — Distillation of Oil or Paraffin by Air or Steam. 

pipe d, it will be found that even solid paraffin will distil over 
practically without decomposition. 

If the paraffin be heated highly alone and distillation attempted, 
it rapidly decomposes, leaving a charred carbon mass. 

From these experiments it is evident that the best method 
of vaporising a hydrocarbon oil containing heavy as well as light 
hydrocarbons is to heat the oil in a vaporiser to a moderate 
temperature, say about 300 C, and then pass air over it also 
heated to about the same temperature. By treating it in this 
way the whole of the oil, light and heavy, can be vaporised 
without fear of decomposing the oil and so producing tarry- 
products or carbon residues. 



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406 Oil Engines 

It is a mistake to use red-hot surfaces in vaporising an oil 
when the vapour formed has to pass through valves ; it is a 
mistake, however, which inventors often make. 

An oil like 'Broxbourne Lighthouse' boiling entirely below 
300 C. might be treated in another way, but the method described 
of passing hot air through would easily vaporise it also, so that no 
other method is necessary. 

The methods of distilling or boiling under reduced pressure 
also supply means of vaporising oil at comparatively low tempera- 
tures ; but the vacuum pan system, although largely applied to the 
sugar industry, has not been applied to the vaporising of oils. 



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407 



CHAPTER II. 

OIL ENGINES. 

Having now discussed briefly the chemical and physical properties 
of the hydrocarbon oils, the reader is in a position to consider the 
mechanical arrangements of oil engines. The lighter oils being so 
easily vaporised were naturally first used in the early forms of oil 
engine. With oils of a specific gravity less than 74 and a flashing 
point as a rule lower than the ordinary atmospheric temperature 
of 1 6° C, such as benzine, benzine naphtha and gasoline, the problem 
of producing an inflammable mixture capable of being drawn into 
an engine cylinder, compressed and exploded, is so simple that no 
complicated considerations trouble the inventor in producing his 
engine. The earlier oil engines accordingly used such light oils. 

Early Oil Engines. — The earliest proposal to use oil as a means 
of producing motive power by explosion appears to be that of 
Street, whose English patent was taken out in the year 1791. 
The first practical petroleum engine, however, was that of Julius 
Hock of Vienna, who produced an engine in 1870. This engine 
operated on the old non -compression system and took in a charge 
of air and light petroleum spray during part of the forward stroke 
of a piston, ignited that charge at atmospheric pressure by means 
of a flame jet and so produced a low-pressure explosion similar to 
that of the Lenoir gas engine. In 1873 Bray ton, an American 
engineer, produced an oil engine shown on p. 153 of this work. In 
that engine heavy oil, it is true, was used having a density some- 
times as high as '85, but this oil was crude unrefined oil flashing at 
about atmospheric temperature. The engine was not a practical 
success, but it was the first compression engine using oil fuel 
instead of gas. 



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408 Oil Engines 

Shortly after the Otto gas engine came into use in 1876, 
several engines of that type were operated by air gas, a ga$ pro- 
duced front the liquid known as gasoline, by drawing air through 
the gasoline and so charging this air with inflammable vapour. The 
air so charged was drawn into the engine cylinder with a further 
supply of air and formed an explosive mixture, which was com- 
pressed and ignited in the usual manner common to Otto cycle 
engines. 

The Spiel petroleum engine appears to be the first engine pf 
the Otto cycle introduced into practice which dispensed with an 
independent vaporising apparatus. In this engine light oil of not 
greater than 725 specific gravity was injected directly into the 
cylinder on the suction stroke, and mixing with the air entering 
the whole of the oil became vaporised at ordinary temperatures 
or at the slightly increased temperature of the engine cylinder, and 
on compression an explosive mixture was obtained which acted 
precisely as the ordinary gas mixture of the Otto engine. Good 
results are obtained by the Spiel engine so far as economy is 
concerned, the consumption being *8i lb. per brake HP per 
hour. The engine, however, never became really popular because 
such light oils as it used were dangerous, and besides legal 
restrictions as to storage and transport of light oils materially 
interfere with the introduction of such an engine. 

Engines using safe burning Oils. — Safe burning oils having a 
flashing point above 73 F. require very different treatment to 
obtain an explosive mixture capable of operating an oil engine, 
and the treatment required varies with the nature of each particular 
sample of oil. Engines now constructed use American and Russian 
petroleums and Scotch paraffin oils without difficulty. Such oils 
vary in specific gravity from 78 to '825 and in flashing point 
from 75 to 152 F. All of the oils in ordinary use have, as 
has been already pointed out, different temperatures at which 
they begin to boil at ordinary atmospheric pressure. The 
temperatures vary from 144 C. to 165 C. (see table, p. 397). 
Engines burning such oils may be divided into three distinct 
classes : 

1 st. Engines in which the oil is subjected to a spraying opera- 
tion before vaporising. 



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Oil Engines 409 

2nd. Engines in which the oil is injected into the cylinder and 
vaporised within the cylinder. 

3rd. Engines in which the oil is vaporised in a device exter- 
nal to the cylinder, and introduced into the cylinder in the state 
of vapour. 

This division into three classes thus refers to the mode of 
vaporising. The method of ignition may also be used to divide 
the engines into different classes : 

1 st. Oil engines igniting by the electric spark. 

2nd. Oil engines ignited by incandescent tube. 

3rd. Oil engines igniting by the heat of the internal surfaces of 
the combustion space. 

Spiel's engine was ignited by means of a flame-igniting device 
similar to that used in Clerk's gas engine described on p. 215 of 
this work, but Spiel's engine is the only one introduced into this 
country which ever used a flame igniter. On the Continent, how- 
ever, flame igniters are not uncommon. Hille's engine uses a 
flame igniter. In this country, however, all methods of ignition 
both in gas and oil engines have for practical purposes been dis- 
placed by the hot tube and the hot surface igniters. 

Engines in which the Oil is subjected to a Spraying Operation 
before Vaporising. — The engines at present in use in this country 
falling under this head are the Priestman arid the Samuelson. In 
both the oil is sprayed before being vaporised. The principle 
of the spray producer used is that so well and widely known in 
connection with the atomisers or spray producers used by per- 
fumers. Fig. 187 shows such a spray producer in section. In 
this elementary form of spray producer an air blast passing from 
the small jet a crosses the top of the tube b, and creates within 
that tube a partial vacuum. The liquid contained in the glass 
bottle c flows up the tube b, and issuing at the top of the tube 
through a small orifice is at once blown into very fine spray by 
the action of the air jet. If such a scent distributor be filled 
with petroleum oil such as Royal Daylight or Russoline, the oil 
will also be blown into fine spray, and it will be found that this 
spray can be ignited by a flame and will burn, if the jets be pro- 
perly proportioned, with an intense blue non-luminous flame. 
The earlier inventors often expressed the idea that an explosive 



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mixture could be prepared without any vaporisation whatever by 
simply producing an atmosphere containing inflammable liquid in 
extremely small particles distributed throughout the air in such 
proportion as to allow of complete combustion. The familiar 
explosive combustion of lycopodium, and the disastrous explosions 
caused in the exhausting rooms of flour mills by the presence of 
finely divided flour in the air, have also suggested to inventors the 
idea of producing explosions for power purposes from combustible 
solids. Although, doubtless, explosions could be produced in that 
way, yet in oil engines the production of spray is only a preliminary 
to the vaporisation of the oil. If a sample of oil be sprayed in 
the manner just described and injected in a hot chamber also 

filled with hot air, then the 
oil so sprayed will at once 
pass into a state of vapour 
within that chamber, al- 
though the air should be at 
a temperature far below the 
boiling point of the oil. 
The spray producer, in fact, 
furnishes a ready means of 
saturating any volume of air 
with heavy petroleum oil to 
the full extent possible from 
the vapour tension of the oil 
at that particular tempera- 
ture. The oil engines about to be described are in reality ex- 
plosion gas engines of the ordinary Otto type with special arrange- 
ments to enable them to vaporise the oil to be used. The author 
will, therefore, only describe such parts of the engines as are 
necessary to treat the oil and to ignite it. 

Priestman Oil Engine. — Fig. 188 is a vertical section through 
the cylinder and vaporiser of the Priestman engine. Fig. 189 
is a section on a larger scale showing the vaporising jet and the 
air admission and regulation valve leading to the vaporiser. 
Fig. 190 is an elevation on a smaller scale showing the general 
arrangement of the engine. 

In this engine oil is forced by means of air pressure from the 




Fig. 187.— Perfume Spray Producer. 



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reservoir a through the pipe b to the spraying nozzle c, and air 
passes from the air pump d by way of the annular channel b into 
the sprayer c, and there meets the oil jet issuing from a, the air 
impinges upon the oil, breaks it up in spray, and the air charged 
with oil spray flows into the vaporiser e, which vaporiser is 
heated up in the first place on starting the engine by means of a 
lamp g. In the vaporiser the oil spray becomes oil vapour 
saturating the air within the hot walls, and on the out-charging 
stroke of the piston the mixture passes by way of the inlet valve 




Fig. 188.— Priestman Oil Engine (section through vaporiser and cylinder). 

h into the cylinder. The valve 1 allows air to flow into the 
vaporiser to displace its contents, and furnish air to be further 
saturated with oil spray and vapour for the next stroke. The 
cylinder k is thus charged with a mixture of air and hydrocarbon 
vapour, some of which may exist in the form of very fine spray. 
The piston l then returns and compresses the mixture, and when 
the compression is quite complete an electric spark is passed 
between the points m and a compression explosion is obtained 
precisely similar to that obtained in the gas engine. The piston 



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412 



Oil Engines 



moves out expanding the ignited gases, and on the return' stroke 
the exhaust valve n is opened and the exhaust gases are discharged 
by way of the pipe o round the jacket p inclosing the vaporising 
chamber. The vaporising chamber is thus kept hot by the 
exhaust gases whenever the engine starts, and it remains suffi- 
ciently hot without the use of the lamp g. To obtain the electric 
spark a bichromate battery is used and the Ruhmkorf induction 
coil. The spark is timed by contact pieces q operated from the 
eccentric rod r used to actuate the exhaust valve and the air 
pump for supplying the oil chamber and the spraying jet. Fig. 
189 shows the spraying nozzle on a larger scale. The oil jet 
passes through the small aperture a and meets the air discharging 





Fig. 189.— Priestman Oil Engine (vaporising jet and air valve). 



from the annulus b by way of the re-entrant nozzle r. Very fine 
spray is produced in this manner. 

To start the engine the hand pump s is operated to get up a 
sufficient pressure to force the oil through the spraying nozzle, 
and oil spray is formed in the lamp G, and the spray and air 
mixing produce a blue flame which heats the vaporiser. The 
hand pump is operated until the vaporiser is sufficiently hot to 
start the engine. The fly wheel is then rotated by hand, and the 
engine moves away. The eccentric shaft is operated from the 
crank shaft by means of toothed wheels which reduce the speed 
to one-half the revolutions of the crank shaft. The charging 
inlet valve is automatic. 

The Priestman engine was the first engine capable of using 



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4*3 




q JJ A J 

V 

J—J I 



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41 4 Oil Engines 

heavy safe burning oils. It is somewhat complex in its con- 
struction, and suffers under what the author considers the great 
disadvantage of igniting by the electric spark, but it is the 
pioneer, and the Messrs. Priestman deserve the greatest credit for 
their ability and pertinacity in overcoming the formidable diffi- 
culties in the way of getting an efficient explosive mixture from 
heavy oils. Large numbers of the engines are in operation and 
appear to give satisfaction. The sizes made by Messrs. Priestman 
vary from i horse nominal to n horse nominal, and twin or 
double cylinder engines have been made of 25 horse nominal. 

In the Priestman engine governing is effected by throttling the 
oil and air supply. For this purpose the governor operates on 
the butterfly valve t and on the plug cock / connected to it, by 
means of the spindle f. The air and oil are thus simultaneously 
reduced, and the attempt is made to maintain the charge entering 
the cylinder at a constant proportion by weight of oil and air 
while reducing the total weight and therefore volume of the charge 
entering. The Priestman engine therefore gives an explosion on 
every second revolution under all circumstances whether the 
engine be running light or loaded. The compression pressure of 
the mixture before ignition is, however, steadily reduced as the 
load is reduced, and at very light loads the engine is running 
practically as a non-compression engine. This is a grave dis- 
advantage, as the fuel consumption per I HP rises rapidly with the 
reduction of compression. 

Tests and Oil Consumption. — Professor Unwin made a test of 
the Priestman engine at the Royal Agricultural Show at Plymouth 
in 1890. The engine tested was a 4^ HP nominal, cylinder 
8*5 in. diameter, 12 in. stroke, normal speed 180 revolutions per 
minute. The oil used was that known as Broxbourne Light- 
house, a Scotch paraffin oil produced by the destructive distillation 
of shale. Its density is *8i and flashing point about 152 F. 
The analysis of the oil by Mr. C. J. Wilson gave : 

Carbon 86*oi per cent. 

Hydrogen 1390 „ 

Deficiency "09 ,, 

100*00 per cent. 
By calculation the heating value is 19,700 thermal units F. 



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Oil Engines 41 5 

per lb. This is the total heat evolved including heat of con- 
densation of steam to the liquid state. The principal results 
given by the test were as follows : 

Indicated HP 5*243 

Brake HP 4*496 

Duration of trial 150 minutes 

Mean speed (revolutions per minute) .... 179*5 

Mean available pressure (lbs. per square inch) 33 '9° 

Explosions per minute 8975 

Oil consumed per IHP per hour (lbs.) .... 1*066 

Oil consumed per brake HP per hour (lbs.) . i -2 43 
The heat account is— 

Total heat shown by indicator 12*67 

Heat given to jacket water 53*39 

Exhaust waste and other losses 33 '96 



In 1892 Professor Unwin made another trial of a 5 HP Priest- 
man oil engine at Hull, in the course of which he used both 
Russoline oil and Daylight oil. The engine was of the same 
dimensions as the Plymouth engine, that is 8*5 ins. cylinder and 
1 2 ins. stroke. The volume swept by the piston per stroke was 
•395 cubic feet, and the clearance space in the cylinder at the end 
of the stroke was *2io cubic feet. The small air-compressing 
pump supplying the spray producer discharged -033 cubic feet per 
stroke. The total weight of the engine was 36 cwt, including a 
fly-wheel of 10 cwt. The principal results obtained were as 
follows : 

IHP 

Brake HP 

Mean speed (revolutions per minute) . 
Mean available pressure (revolutions per minute) . 
Oil consumed per IHP per hour .... 
Oil consumed per brake HP per hour . 

With Daylight oil the explosion pressure was 151*4 lbs. per 
square inch above atmosphere, and with Russoline 134*3 lbs. 
The terminal pressure at the moment of opening the exhaust 
valve with Daylight oil was 35*4 lbs., and with Russoline 337 per 
square inch. The compression pressure with Daylight oil was 
35 lbs., and with Russoline 27*6 lbs. pressure above atmosphere. 



Daylight 
9369 • 
7722 . 


Russoline 
7408 

6765 


204*33 • 
S3*a 
•694 lbs. 
'842 ,, 


20773 
4i'38 
•864 lbs. 

*94 6 .. 



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416 Oil Engines 

Analyses were made of the samples of Daylight and petroleum 
by Mr. C. J. Wilson, F.C.S. 

Daylight Russoline 

Carbon . . 84 62 per cent. . 85*88 per cent. 

Hydrogen. . 14-86 ,, ... 14*07 „ 

Oxygen ... 52 ... -05 ,, 

100 -oo per cent. 100 *oo per cent. 



Specific gravity at 6o° F. 7936 -8226 

Flashing point . . 77 F 86° F. 

The total heat of combustion of Daylight oil calculates out at 
21,490 British thermal units, and for Russoline at 21,180 British 
thermal units. 

Professor Unwin calculates the amount of heat accounted for 
by the indicator as 18*8 per cent, in the case of Daylight oil, and 
15-2 in the case of Russoline oil. Fig. 191 is a diagram taken by 
Professor Unwin, and published in his paper read before the 
Institution of Civil Engineers in 1892. The largest diagram 
is a full-power diagram ; the diagram in dotted lines is half power ; 
and the small light-line diagram shows the card given by the engine 
when working without load. The various particulars of clearance 
spaces, maximum pressure, pressure of compression, and stroke 
volume are clearly shown upon the illustration. From these figures 
it will be seen that the Priestman oil engine worked on a con- 
sumption of '946 lb. of Russoline oil per brake HP per hour, and 
•842 lb. of Daylight oil per brake HP per hour. 

Professor Unwin states that the oil used in starting the engine 
was insignificant in quantity, being only about one pound of oil 
in each of the two trials in which it was measured. 

The Samudson Oil Engine. —Messrs. Samuelson's engine is 
constructed under the Griffin patents, and it resembles Priestman's 
in subjecting the oil to the preliminary process of spraying before 
vaporising, and in it also the vaporiser is heated during the run- 
ning of the engine by the exhaust gases. It differs, however, from 
the Priestman engine in the methods of igniting and governing. 
The tube igniter is used, and, instead of reducing the power of 
the explosions as is done by Messrs. Priestman, the governing 
device so operates that when speed becomes too high, the air 
supply is entirely cut off, and the exhaust valve is also closed. 



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The exhaust valve is closed after the combustion products of 
the last explosion have been discharged from the cylinder, the 
piston consequently moves out, expanding the contents of the 
compression space. 

The oil valve is simultaneously shut off in the sprayer, so that 
no oil is injected. 

Fig. .192 is a section of the Griffin patent oil sprayer. The 
air enters by. way of the passage a, and discharges through the 
nozzle a', thereby creating a partial vacuum in the annular space 
b formed between the air nozzle and the oil nozzle. The passage 



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Fig. 191. — Priestman Oil Engine (diagram, Unwin). 

b 2 connects to the oil-supply chamber b 7 by way of a spraying valve 
c attached to a plunger stem c'. The air pressure, when admitted, 
forces down the plunger c', and thus opens the valve c against the 
pressure of the spring. Oil thus passes up the passage b 2 from the 
chamber b', and is discharged with the air from the nozzle a 7 in a 
state of fine spray. 

Whenever the air pressure is removed from the plunger c', the 
spring forces the valve to its seat, and cuts off the oil supply. 
The air pressure is maintained at from 12 to 15 lbs. above 

E E 



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4i8 



Oil Engines 



atmosphere by a pump driven from an eccentric on the valve 
shaft. 

The vaporiser is shown in longitudinal transverse section, plan 
and end elevation at fig. 193. e is the vaporiser, made of cor- 
rugated outline, and surrounded by the exhaust jacket f. The 
air is admitted to the vaporiser from the atmosphere by the 
adjustable perforated plate g, and the spray nozzle is attached 
at a point h, and discharges the spray into the centre of the 
vaporiser. 




Fig. 192.— Samuelson (Griffin) Oil Sprayer. 

So far the arrangements closely resemble those of the Priestman 
engine ; but, instead of using the electric spark for igniting, the 
incandescent tube is adopted, and an incandescent metal tube is 
heated and kept hot by an ingenious lamp shown at fig. 194. In 
this lamp oil is admitted to the chamber j by the pipe k, and it is 
maintained at a constant level there by means of the overflow pipe l. 
A short piece of wire m is immersed in the oil, and the oil runs up 
the wire and covers the bent part by reason of capillary attraction. 
Air under pressure is admitted by way of the pipe n adjusted by 



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419 



the screw n', and it passes to the nozzle o, striking upon the bent 
part of the wire m. The air thus blows the oil off the wire, and 




^™"^ 












— \£—^ 


m m - 


f^ 








^1 


* 








c 





Fig. 193.— Samuelson Engine Vaporiser. 

at the same time the jet sucks in a further supply of air through 
holes p, and the mixed air and oil spray pass through the tube q 
to the asbestos- lined funnel R ; on igniting the mixture within this 




Fig. 194.— Samuelson Engine Spray Lamp. 

funnel, it burns with a fierce blue flame, and heats up the igniter 
tube s ; this tube opens into the engine cylinder, and ignites the * 
mixture when it is compressed. To start the engine, the air pump 

E E2 



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420 Oil Engines 

is worked by hand until the required pressure is obtained ; air is 
then turned on the sprayer, and the spray lighted. By this means 
the vaporiser is heated for about ten minutes from within, the 
burned gases being discharged through a special valve opening 
into the exhaust, which valve is closed when sufficient heat is 
attained. The heating lamp of the incandescent tube is in the 
meantime lighted, and the engine is ready to start. 

No independent tests have been made of the power and oil 
consumption of this engine within the author's knowledge. 

Engines in which the Oil is injected into the Cylinder and 
vaporised within the Cylinder. — The engines at present in use in 
Britain falling under this head are those manufactured and sold 
by Messrs. Hornsby of Grantham, Messrs. Robey of Lincoln, and 
a German engine known as the 'Capitaine.' Messrs. Hornsby 
term their engine the Hornsby- Ackroyd engine, and it is un- 
doubtedly the most successful and simple of this type. 

Hornsby-Ackroyd Oil Engine. — Fig. 195 is a section through 
the vaporiser and cylinder of the Hornsby-Ackroyd engine, and 
fig. 196 shows the inlet and exhaust valves also in section placed 
in front of the vaporiser and cylinder section. The main idea of 
this engine is simple in the extreme. Vaporising is conducted 
in the interior of the combustion chamber, which chamber is so 
arranged that the heat of each explosion maintains it at a tem- 
perature sufficiently high to enable the oil to be vaporised by 
mere injection upon the hot surfaces, the heat being also sufficient 
to cause the ignition of the mixture of vapour and air when com- 
pression is completed. The vaporiser a is heated up by a 
separate lamp, the oil is injected at the oil inlet b, and the engine is 
rotated by hand. The piston then takes in a charge of air by the 
air inlet valve into the cylinder, the air passing by the port directly 
into the cylinder without passing through the vaporiser chamber. 
While the piston is moving forward taking in the charge of air the 
oil which has been thrown into the vaporiser is vaporising and 
diffusing itself through the vaporising chamber, mixing, however, 
only with the hot products of combustion left by the preceding 
explosion. During the charging stroke the air enters through the 
cylinder, and the vapour formed from the oil is almost entirely 
confined to the combustion chamber. On the return stroke of 



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421 



the piston air is forced through the somewhat narrow neck a into 
the combustion chamber, and it there mixes with the vapour con- 
tained in it. At first, however, the mixture is too rich in inflammable 




Fig. 195.— Hornsby-Ackroyd Engine 
(section through vaporiser and cylinder). 

vapour to be capable of ignition. As the compression proceeds, 
however, more and more air is forced into the vaporiser chamber, 
and just as the compression is completed the mixture attains 




Fig. 196. — Hornsby-Ackroyd Engine 
(section through valves, vaporiser, and cylinder). 

propef explosive proportions. The sides of the chamber are 
sufficiently hot to cause explosion, and the piston moves forward 
under the pressure of the explosion so produced. 

As the vaporiser a is not water -jacketed, and is connected to 



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422 



Oil Engines 



the metal of the back cover only by the small sectional area of cast 
iron forming the metal neck a> the heat given to the surface by 
each explosion is sufficient to raise its temperature to about 
700-800 C. and keep it there. 

It is a peculiar fact that oil vapour mixed with air will explode 
by contact with a metal surface at a comparatively low tempera- 
ture, and this accounts for the explosion of the compressed 
mixture in the combustion chamber a, which is never really raised 
to a red heat. It has long been known to engineers conversant 
with gas engines that under certain conditions of internal surfaces 
a gas engine may be made to run and ignite with very great 
regularity without incandescent tube or any other form of igniter. 




Fig. 197.— Cylinder Ignitions, Otto Engine. 

if some portion of the interior surfaces of the cylinder or combus- 
tion space be so arranged that the temperature can rise moderately ; 
then, although that temperature may be too low to ignite the 
mixture at atmospheric pressure, yet when compression is com- 
plete the mixture will often ignite in a perfectly regular manner. 
Fig. 197 shows a series of diagrams taken from the ordinary Otto 
engine igniting in this manner without any special igniter, and it 
will be observed that the diagrams are very fairly regular. The 
author has noticed this peculiar fact in connection with one of 
his old engines described on page 184. He placed a stud a, 
fig. 198, in the end of the piston b ; this stud was sufficiently long 
to project the head well into the explosive mixture ; on starting 



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the engine with the ordinary flame-igniting valve and running it 
for 15 minutes in the usual way, it was found that the flame- 
igniting arrangement could be entirely stopped from action and 
•the engine run regularly, the mixture igniting only because of the 
incandescent head of the bolt a, which projected into the explosive 
mixture after compression and ignited only when the mixture was 
fully compressed. In this arrangement, however, the bolt a was 
found to attain a high red heat. 

It is a curious and interesting fact that with heavy oils ignition 
is more easily accomplished at a low temperature than with light 
oils. The explanation seems to be that in the case of light oils 
the hydrocarbon vapours formed are tolerably stable from a 
chemical point of view, but the heavy oils very easily decompose 
by heat and separate out 
their carbon, liberating the 
combined hydrogen, and at 
the moment of liberation 
the hydrogen being in what 
chemists know as the nas- 
cent state very readily enters 
into combination with the 
oxygen beside it. In this 
manner combustion is more 
easily started with a heavy 
oil than with a light one. 

Messrs. Hornsby's vaporiser is of D shape, the rounded part 
above and the straight part of the D below. 

To start the engine the vaporiser is heated by a separate 
heating lamp, which lamp is supplied with an air blast by means 
of a hand-operated fan. This operation should take about nine 
minutes. The engine is then moved round by hand, and starts in 
the usual manner. The oil tank is placed in the bedplate of the 
engine. The air and exhaust valves are driven by cams on a valve 
shaft. 

Figure 199 is a general view of the external appearance of the 
engine, from which it will be seen that the governing is effected 
by a centrifugal governor. This governor operates a bye pass 
valve, which opens when the speed is too high and causes the oil 




Fig. 198.— Clerk Engine with bolt igniter. 



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424 Oil Engines 

pump to return the oil to the oil tank. The fan and starting lamp 
will be seen in the lower part of the illustration. 

Tests and Oil Consumption. — Messrs. Hornsby's engine was 
exhibited at the Royal Agricultural Show at Cambridge, and after 
an exhaustive test by the judges of the show in competition with 
engines by nine other makers, the Hornsby engine was awarded 
the first prize of 50/. The engine tested was given as of 8 brake 
HP, and its dimensions were — diameter of cylinder 10 in., 
stroke 15 in., weight of engine 40 cwt. During the trials, 
according to Professor Capper's report, the engine ran without 




Fig. 199. — Hornsby- Ackroyd Oil Engine. 

hitch of any kind from start to finish. Its action was faultless. 
One attendant only was employed all through the trials, and 
started the engine easily and with certainty after working the hand 
blast to the lamp for 8 minutes. During three days' run the 
longest time taken to start was 9 minutes, and the shortest 
7 minutes. When the engine stopped each day the bearings 
were cool and the piston was moist and well lubricated ; the 
revolutions were very constant, and the power developed did not 
vary one quarter of a brake HP from day to day. The oil 
consumed, reckoned on the average of the three days' run, was 
•919 lbs. per brake HP per hour. The oil used was Russoline, 



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Oil Engines 425 

sold in Cambridge at that time at the price of 3f </. per gallon. 
At this rate the cost for oil per brake HP was j</., and this 
included all the oil used for the starting lamp. 

Mr. C. F. Wilson, F.C.S., has made an analysis of the 
Russoline oil used for the purpose of testing the oil engines 
exhibited at Cambridge, and found that the specific gravity at 
6o° F. -824, the flashing point (Abel test) 88° F., the total heat of 
combustion was 1 1*055 calories, but after deducting for the heat 
due to the condensation of water vapour this reduced to 10*313 
calories. The oil contained 14*05 per cent, hydrogen. Mr. 
Wilson makes the observation that this oil appears to be very 
constant in composition, because a similar oil examined by him a 
year before gave 1407 per cent, hydrogen, and a corrected 
calorific value of 10 3 calories, so that the two samples supplied 
at an interval of a year were practically constant in com- 
position. 

The mean power exerted during the three days' trials was 
8*35 brake horse. At a subsequent full-power trial of the same 
engine at the show, a brake HP of 8*57 was obtained, the 
engine running at a mean speed of 239-66 revolutions per 
minute and the test lasting for two hours ; the indicated power 
was io*3 horse, the explosions per minute 119*83, the mean 
effective pressure 28*9 pounds per square in., the oil used per 
IHP per hour was Si and per brake HP per hour '977 pounds. 
According to Professor Capper the heat account of the engine 
was : 

Heat shown on indicator diagram IHP . . . 16*9 per cent. 

Heat rejected in jackets 29*5 ,, 

Heat rejected in exhaust and other losses . 53*6 „ 



In these tests, however, Professor Capper erroneously takes 
the corrected heat value of the oil instead of the total heat value. 
In determining the absolute efficiency of any engine, it is neces- 
sary to take as a basis the total amount of heat evolved by the 
combustion from the atmospheric temperature to the atmospheric 
temperature again. The author has recalculated these figures, and 
finds the correct heat account below : 



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426 Oil Engines 

Heat shown on indicator diagrams per IHP 
Heat rejected in jackets .... 
Heat rejected in exhaust and other losses 



15*3 per cent. 

26*8 

57*9 



In a test of this engine made at the same time but 
half-power, the brake HP developed was 4-57 at 235-9 revolu- 
tions per minute, and the oil used per brake HP per hour was 
i*49 pounds. On a four hours' test with this engine running 
entirely without load at 240 revolutions per minute it was found 
that it consumed 4*23 pounds of oil per hour. Fig. 200 is a card 

lbs. per sq. in. 
absolute 



/TV 

no 
wo 

SO 

90 

4-0 






















































































































20 
























O 





















s 



'9 i-O // cb. ft. 



Brake HP, 8*57; indicated HP, 10*3 ; diam. of cylinder, 10"; stroke, 15"; revs, 
per min. 239*66 ; explosions per min. 1 19*83 ; mean pressure, 28*9 lbs. per sq. in. ; 
pressure of explosion, 113 lbs. per sq. in. above atmos. ; pressure of compression, 
50 lbs. ; oil per IHP hour, '8i lbs. ; oil per BHP hour, '977 lbs. 

Fig. 200.— Hornsby-Ackroyd Oil Engine (diagram). 
Average card, two hours' full power trial. Russoline oil. 

from the Hornsby engine, being an average card of the two hours' 
full-power trial. The cylinder volume is given in cb. ft. and the 
compression space is also given. From this diagram it will be 
observed that the average pressure, the maximum pressure and 
the pressure of compression are very low, and that consequently a 
large cylinder is required to develop a given power, while it is 
worth observing how beautifully regular is the ignition obtained by 
the simple device of firing from the surfaces of the hot combustion 
chamber. 

Robey Oil Engine. — The Robey oil engine is constructed in 



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427 



accordance with the patents of Messrs. Richardson and Norris 
and it very closely resembles the Hornsby-Ackroyd engine. 
Like the Hornsby engine, it depends upon the heat of the 
combustion space walls both for vaporising and igniting, and 
the governing is effected by diminishing the oil supply. It 
differs, however, from the Hornsby engine in this, that the com- 
bustion chamber is made with a water jacket, and an inner 
lining is inserted from behind, which lining stands clear of the 
water-jacketed part and becomes hot by the explosion. Fig. 201 
is a section showing one arrangement of the combustion chamber 
of the Robey engine. The 
liner a is introduced into 
the combustion chamber 
from behind, and it is easily 
removed when it is desired 
to clean or repair. The 
engine also differs, it will be 
observed, in the position of 
the inlet and exhaust valves. 
The charge, instead of pass- 
ing directly into the cylinder 
as in the Hornsby engine, 
passes first outside the com- 
bustion space into the cylin- 
der. The author is unaware 
of any official test of this 

engine, but fig. 202 is a diagram taken by him from a Robey oil 
engine of 6 in. cylinder and 9 in. stroke running at 260 revolu- 
tions per minute, and using American oil having a specific gravity 
of -857 at 50 F. The diagrams from Messrs. Hornsby's and 
Robey's engines prove that this system of ignition and vaporising 
supplies a very regular and effective ignition. 

Capitaine Oil Engine. — The Capitaine oil engine resembles 
the Robey engine in surrounding the combustion chamber with a 
water jacket, and in introducing an internal liner kept clear of the 
water-jacketed sides to give sufficient heat for the purpose of vapo- 
rising and igniting. An engine of this type was entered for trial at 
the Royal Agricultural Show at Plymouth, and it was declared at 




Fig. 201.— Robey Oil Engine 
(section through combustion space). 



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Oil Engines 



5 brake HP, cylinder 7J in. diameter, stroke i\ in., speed 300 
revolutions per minute, weight 17 cwts. The engine was designed 
to use Tea Rose oil, and the adjustments were found to be un- 
suitable for the use of Russoline oil, which was the oil settled by 
the judges for use during competition. The engine was therefore 
withdrawn from the competition, and the author is unaware of 
any official tests. In his report, however, Professor Capper says 
that using Tea Rose oil the engine runs at 300 revolutions per 
minute and develops 4^ brake HP, starting from the moment 
of heating the vaporiser in about five to ten minutes. Fig. 203 
is a section through the vaporiser and combustion chamber, a 
is the inlet valve operating automatically. It contains a central 



too 
Bo 

60 
+0 

so 





Fig. 202.— Robey Oil Engine (diagram, Clerk). 



spindle b, having at the point of it a valve seat b. The valve a 
has thus two seats, one the usual external seat and the other an 
internal seat, closing on its valve seat b. The spindle b operates 
within a hollow, having a hole c opposing the oil supply pipe d. 
e is the vaporiser, which is surrounded by a non-conducting 
casing f, which in turn is inclosed in a metal casing g within the 
combustion space h. i is the water jacket. 

To start the engine the vaporiser is heated by a hand spirit 
lamp. This operation takes from five to ten minutes, and according 
to Professor Capper the engine then starts away very easily. On the 
suction stroke the air inlet valve opens, thereby opening also the 



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429 



internal valve, and air passes into the cylinder, mostly passing round 
outside the casing. A portion, however, passes through the centre of 
the valve, and with it enters the oil from the pipeD. A small quantity 
of oil and air thus passes through the centre of the vaporiser e, 
and the vapour enters the cylinder to form mixture for explosion. 
Upon compression the compressed mixture ignites at the internal 
hot surfaces of the vaporiser e. 

The vaporiser e, with its non-conducting material f and 
outer casing g, is all immersed in the flame of the explosion ; but 
the vaporiser e becomes hottest because it is not subject to the 
cooling action of the air supply, which mostly passes round be- 
tween the casing f and the 
combustion chamber. Only 
a small portion of air passes 
through the hole c with the 
oil entering the pipe; d ; the 
surface g also radiates more 
heat to the cold walls, so that 
the vaporiser is kept at the 
highest temperature by the 
repeated explosions. 

The oil pump used in the 
Capitaine engine is of peculiar 
construction. Fig. 204 is a 
section. The plunger a is 
operated by bell crank lever, 
roller and cam, actuated in 
the usual way ; and a slide 
valve b is actuated also by 

lever c and cam d ; the plunger is packed by leather packing, 
and operates in a glycerine bath f. Oil g floats on the top of 
the glycerine bath, and is discharged through the slide valve b. 
In this way the plunger a is caused to operate in a space of ample 
capacity. 

Engines in which the Oil is vaporised in a Device external to the 
Cylinder, and introduced into the Cylinder in the state of Vapour. — 
Engines falling under this class are manufactured by Messrs. 
Crossley, Tangyes, Fielding & Piatt, Campbell Gas Engine Co., 




Fig. 203.— Capitaine Oil Engine 
(section through vaporiser). 



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430 



Oil Engines 



Ltd., the Britannia Co., Clarke, Chapman & Co., Weyman & 
Hitchcock, and Wells Bros. 

Crossley Brothers' Oil Engine. — Fig. 205 shows the general 
appearance of Messrs. Crossley's oil engine. In this engine a 
separate vaporiser is arranged, communicating with the cylinder 
by a vapour valve. The engine is ignited by an incandescent 
tube, and both incandescent tube and vaporiser are heated by 
the same lamp. The exhaust and air-inlet valves are placed in 
opposition to each other, the air-inlet valve being automatic and 
above the exhaust valve ; both open into the cylinder combustion 

space. The exhaust valve 
Q Q is actuated in the ordinary 

manner from the valve 
shaft. The governor is an 
ordinary rotating governor 
of the hit-and-miss type, 
or in the small engines 
an inertia governor, and 
when the speed is exces- 
sive a link is intercepted 
which ordinarily opens the 
vapour valve, and the valve 
remains closed. No charge 
is then admitted to the 
cylinder. The vapour valve 
upon opening allows the 
suction of the piston to 
draw in a charge of oil to 
the vaporiser, and oil, vapour and air from the vaporiser to the 
cylinder. The charge admitted to the vaporiser is thus heated 
during the period of an entire forward stroke. The air-inlet valve 
is opened by the vacuum caused by the piston, and part of the 
air, on its way to the cylinder, passes first through a heated coil, 
and then through the vaporiser. The heated air charge thus 
carries off the oil vapour through the vapour valve. 

Messrs. Crossley have used several lamps for the purpose of 
heating, but the type of lamp now used by them, and indeed by 
many others, is that best explained by a description of a small 




Fig. 204.— Capitaine Oil Engine 
(section through oil pump). 



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lamp sold as the Etna lamp. This lamp is shown in section and 
plan at fig. 206, and its action and construction are as follows : 

The lamp comprises a stout brass oil- and air-containing vessel 
a, having fitted in it a small air pump b. This pump projects 
within the vessel a, and has at its lower end a pump valve opening 
inwards, which allows the air to pass from the pump into the 
vessel, but prevents it leaking back into the pump. The pump 
leathers cup downwards, to close tight when the air is compressed ; 
but when the piston is withdrawn the air passes the leathers on 




Fig. 205. — Crossley Oil Engine. 

the up-stroke, so that no second valve is required. The piston 
leathers act as a valve in the manner so well known in connection 
with pneumatic tyre inflating pumps. The vessel a has also an 
oil filter c, an air-relief pin d, and above it carries the lamp proper, 
consisting of a continuous arrangement of tubes and passages, 
e, f, g, h, which communicate with the oil in the vessel a by the 
pipe e, which dips to nearly the bottom of the vessel. The tube 
e leads from the oil vessel to the square coil f, seen more clearly 
in dotted lines on the plan. The tube g leads from f into a pas- 
sage shown in the casting h. The casting is drilled out to carry a 



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Oil Engines 



fine nozzle piece i, fitted on as shown. A hood or sleeve J is 
slipped over the whole tube arrangement. The sleeve has two large 




Fig. 206.— Etna Lamp. 

air inlet holes k, one of which is clearly seen in the section. Smaller 
holes are made in the sleeve opposite the square tube piece f. 



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Oil Engines 433 

To start the lamp, the vessel a is partly filled with petroleum 
by way of the oil cup c, the cap is screwed on, and the saucer- 
shaped depression in the top of the vessel a is filled with spirit 
and ignited. The flame produced heats up the tube arrangement 
and the funnel or hood. About one minute suffices to heat it to 
a high enough temperature for starting. The air pump b is now 
operated, and air is forced into the vessel a under pressure, and 
it presses upon the surface of the oil and forces it up the tube e. 
It rises in the tube till it reaches the hot part, when the oil is 
caused to boil and vapour is generated ; this vapour issues at the 
small jet 1, and as this jet is small the pressure rises. The vapour 
jet ignites at the external flame, and a powerful flame shoots into 
the hood J, and by its motion sucks in a charge of air by way 
of the slots. The flame leaving the hood J is thus mixed 
with air, and a powerful blue smokeless flame leaves the hood, 
which flame is capable of heating up metal surfaces to incan- 
descence without depositing soot. The flame plays on the tubes 
e, f, g, and so supplies heat to the oil. A small pressure of air is 
required, and if excess has been pumped in, it is discharged by 
■the plug d. 

If too great an air pressure be given, the air will force the oil 
up to the jet 1, but with the correct pressure the air just keeps the 
oil high enough in the tube e to generate sufficient vapour. Pegs 
are arranged to allow the tubes to be cleaned. A few strokes of 
the air pump, supply air sufficient to operate the lamp for 
hours. 

Fig. 207 shows a vertical section and a sectional plan of the 
Crossley vaporiser and incandescent tube. The sectional plan is 
taken on the line x y of the vertical section, through the vapour 
admission and igniting port of the engine, and the sectioned metal 
is part of the back cover or end of the combustion chamber. The 
combustion chamber is thoroughly water-jacketed like the rest of 
the engine. When the suction stroke of the engine begins, the 
vapour valve g is opened by the bell crank lever, operated from 
the valve shaft by a link. This link is controlled by the 
governor so as to either hit or miss the cam by a knife-edge 
contrivance. While the engine is at work, therefore, the valve G is 
either entirely opened or entirely closed on the charging stroke, 

F F 



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Oil Engines 



and the governing is the same as the usual gas engine governing. 
When the valve g is opened considerable suction to the engine 
cylinder is caused, as the air inlet valve to the cylinder is 
automatic, and is held to its seat by a spring. The vaporiser 
passages communicate with the vapour valve g, and a small 
quantity of heated air passes over the oil and carries off the 
vapour. The vaporiser is heated by the lamp, and the products 



JC- 




Fig. 207.— Crossley Vaporiser. 

of combustion are discharged by the funnel d. Fig. 207 shows 
this very clearly. The lamp produces a powerful Bunsen flame, 
which first heats up the igniter c to incandescence, then it plays 
on the vaporiser having drilled holes bbbb, and the gases pass 
up the funnel. A casing surrounds the heated parts. 

The funnel has an air space e surrounding it, which is divided 
up by louvre projections. Small holes f open to the air at the 
top. When the vapour valve g is opened, air is drawn in by the 



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435 



holes f, passes down the air space e, guided from side to side by 
the baffle or louvre projections ; the air current reaches the passage 
b and passes into the vaporiser, above the oil pipe or channel 
a. The air there meets the liquid oil, also sucked in by the 
partial vacuum, and the hot air carries the oil through the 
vaporiser along the passage b, down along a similar passage 
under it, and along b to the vapour valve g. The oil is thus 
thoroughly vaporised and carried away by the hot air current. 
One important point to insure effective vaporisation is to heat 
the air thoroughly, and reduce its quantity as much as possible. 
This is done by limiting the dimensions of the openings f. The 
air and oil vapour pass by the valve g and admission port to the 




UJ 




*f^':|^ 




t=J ""*" 


e 



Fig. 208. — Crossley Oil Measurer. 

engine cylinder, and there mix with the air entering by the 
automatic air inlet valve at the top of the cylinder ; the mixture is 
then compressed and ignited when compression is completed by a 
timing valve of the ordinary Crossley type connected to the 
igniting tube c. The igniting tube c communicates with the ad- 
mission passage by a small hole on the under side passing through 
the casting of the vaporiser. The tube c is surrounded by a cast- 
iron protecting tube to prevent too rapid oxidation. 

The incandescent tube c has at its outer end an inlet suction 
valve, which opens inward at each suction stroke, and thoroughly 
clears out the burned gases of the last explosion, and so insures 
certain explosion when the compressed mixture is admitted. 

The oil supplying and measuring arrangements are very perfect. 

f f 2 



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436 Oil Engines 

The pump does not measure the oil, but only supplies it in ex- 
cess to a very simple measuring device. Fig. 208 is a diagrammatic 
section of that device. The hole a is the oil-measuring aperture, 
and it opens to the small lift valve £, which communicates with 
the pipe a, fig. 207 ; oil is spirted from the end of the pipe c by 
the pump, and it fills the hole a up to the top ; the excess oil 
drains away to the chamber d and returns by the pipe e to the 
reservoir in the tank in the base of the engine. When the 
opening of the vapour valve causes suction in the vaporiser, the 
valve b lifts, and the oil charge contained in the hole a is sucked 
in, air following it to clear it all out into the vaporiser. By this 
device a constant volume of oil is measured into the vaporiser for 
each working stroke of the engine, and this measurement is 
accurate and unvarying, even when the speed of the engine 
changes. 

The oil pump is large enough to discharge a considerable 
excess of oil, and one pump plunger serves both for vaporiser and 
lamp. The pump discharges through two lift valves, one of 
which is loaded by a spring to lift at about 20 lbs. per sq. in., and 
the other is not loaded but lifts freely. The loaded valve dis- 
charges to the vaporiser oil measurer, and the free valve discharges 
to the lamp. 

The lamp operates on the principle of the Etna lamp, but 
instead of a coil, a gun-metal chamber is used, having a central 
aperture for flame, a jet of small diameter at the foot of the 
central aperture, and a pipe leading to the connected space from 
the oil pump. The jet is very fine, and as the oil finds its way into 
the chamber, vapour is formed which issues from the jet and 
forms with air a Bunsen flame which heats up the lamp chamber, 
and heats to incandescence the igniting tube as well as the 
vaporiser and air heater. The lamp is started in the usual 
manner by heating with flame from some oil- soaked rag or waste ; " 
this is done to avoid the use of any light oils for starting. 

It is found by experience that the vapour jet hole should be 
small enough to generate a pressure of not less than 20 lbs. per 
sq. in., and by the simple device of two discharge valves, one 
loaded and one free, the vaporiser is fed with oil at 20 lbs. pres- 
sure. The vapour generated is thus kept at 20 lbs. as the vapour jet 



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Oil Engines 437 

produces sufficient resistance. If the pump sends too much oil, 
then the liquid level in the vaporiser rises, and the increase in 
vapour pressure holds the lift valve down and allows more oil to 
discharge by the loaded valve. The lamp thus just gets oil 
enough to generate vapour at 20 lbs. By keeping the lamp 
chamber under considerable pressure it is found that the small jet 
hole does not choke up ; if the pressure be lowered, however, the 
hole rapidly chokes up with carbon. This is obviously due to 
the fact that by boiling under high pressure the oil decomposes 
into lighter oils which do not readily carbonise, as explained in the 
previous chapter. In stopping the lamp it should be stopped 
suddenly by dropping the pressure rapidly ; by doing this the 
hole escapes being choked up. Every morning before starting the 
vapour hole should be pricked out with a very fine needle. 

The vaporiser should be cleaned out every week ; this is 
accomplished by taking off the scraped cover, which is held on by a 
bolt, and putting in a steel rimer in succession to the four bored- 
out holes of the vaporiser. By turning round the rimer the 
carbon or coke which has formed in a week's run is easily cleared 
out. 

Tests and Oil Consumption. — A Crossley engine, declared of 
7^ brake HP, was tested at the Cambridge Royal Agricultural 
Show. Its dimensions were : Cylinder 7 ins. diameter ; stroke 
15 ins. ; weight 32 \ cwts. ; the speed per minute 210 revolutions. 
During the test the engine ran admirably, and required very little 
attention ; the average time taken to start was 16 minutes, the 
maximum time taken being 19 minutes, and the minimum 13. 
One attendant only was required. As the result of the three 
days' test, the engine developed on an average 6*28 brake HP, and 
consumed '90 lb. of Russoline oil per brake HP per hour. At a 
full-power trial, lasting for two hours, the engine developed 7'oi 
brake HP, and indicated 7*9, running at a mean speed of 200*9 
revolutions per minute. The oil used was 73 lb. per IHP per 
hour, and '82 lb. per brake HP per hour. On a half-power 
trial the engine developed 372 brake HP on a consumption of 
1*33 lb. of Russoline per brake HP per hour, the speed being 
198*4 revolutions per minute. Running entirely without load 
at 190 revolutions per minute, the engine consumed 2*53 lbs. of 



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Oil Engines 



oil per hour. Fig. 209 is an indicator diagram taken from this 
engine, from which it will be seen that the maximum pressure of 
explosion was nearly 240 lbs. absolute, and the pressure of com- 
pression about 80 lbs. absolute. The mean available pressure 
during the two hours' run was 72*2 lbs. per square inch, the mean 
number of cylinder explosions per minute being 75-3. The oil 
consumed by the Crossley engine is remarkably low, '82 lb. of 

lb per Sq. in. 
dbs. 
z+o 

220 

ZOO 

t$0 

i60 

HO 

tZO 

too 

00 
60 
40 



20 
O 



> 
^SZ S^^SS ^^^m ^^2S ^ 

— I 1 ! 1 



'z 



'+ 



Fig. 209. — Crossley Oil Engine (diagram). 
Average card, two hours' full power trial. Russoline oiL 

Russoline oil per brake HP per hour representing an expenditure 
for fuel of "37</. Another trial of the Crossley engine was made 
at the Show with Broxbourne oil. The power indicated was 
8-4, the brake power 7*63, the engine running at a mean speed 
of 199*84 revolutions per minute. The mean effective pressure 
was 63-6 lbs. per square inch, and the oil per IHP per hour, 
•72 lb. ; and per brake HP per hour, 785 lb. Although the 



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Oil Engines 439 

engine runs with less of this oil per HP, yet it is to be remem- 
bered that the oil costs %\d. per gallon, and is not so economical 
from a monetary point of view as Russoline oil. 

Tangye Oil Engine, — This engine is made under Pinkney's 
patents, and it resembles Crossley's oil engine in this, that the oil 
is vaporised in a separate vaporiser, but the air charge is wholly 
passed through the vaporiser to carry the vapour into the cylinder, 
and the air so used is not subjected to any preliminary heating. 
The ignition is effected by incandescent tube. The construction 
and operation are as follows : 

Fig. 210 shows a vertical section and plan of the oil attach- 
ment to a Tangye gas engine. The vaporiser is a bottle-shaped 
vessel a always in direct communication with the combustion 
space of the engine by the passage b. c is the inlet valve to the 
engine ; it is automatic, and is held to its seat by a spring, d is the 
air inlet passage, e is the oil supply aperture which terminates 
in a small hole f opening on the seat of the valve c and conse- 
quently opened and closed by it. g is a coil lamp of the Etna 
type, i is the igniting tube opening to the vaporiser, h is a bracket 
for supporting the lamp g in its successive positions under the 
vaporiser and under the igniting tube, j is a casing surrounding 
the igniting tube, and k a casing surrounding the vaporiser. The 
lever l (plan) operates a slide, which causes the hot gases from the 
lamp, to pass either round the vaporiser or by the tube funnel J. 
To start the engine the lamp g is first lit in the manner of the Etna 
lamp and the vaporiser a is sufficiently heated. The lamp is 
then shifted out on the bracket h, and the tube 1 is raised to 
incandescence. The engine is then ready to start by turning 
the fly-wheel. When in operation, on the suction stroke air 
enters by the valve c, and at the same time oil discharges by the 
aperture f, mixes with the entering air, and falls on the vaporiser 
when it is vaporised, and passes into the cylinder with the air. 
On the compression stroke the inflammable mixture is com- 
pressed and ignites at the igniting tube 1, producing a working 
explosion. When the valve c closes, the oil supply is also 
closed. 

When governing, the governor holds open the exhaust valve 
so that the exhaust gases are alternately drawn into and discharged 



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from the cylinder ; during this action the valve c is held shut by 
its spring, and no oil or air enters the cylinder. When the exhaust 




Fig. 210. -Tangye Oil Engine 



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441 



valve closes again, the oil and air enter the vaporiser and the 
explosions begin again. 

The oil is fed by gravity from an oil reservoir mounted above 




the engine by a pipe to the passage £ ; adjusting devices are 
applied at the reservoir end. 

The engine is a very simple one, but in the author's opinion 



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Oil Engines 



all systems of feeding oil by gravity are bad, and with large 
engines such systems are likely to be dangerous. 

The author is unaware of any independent tests of this 
engine, 

Fielding & Platfs Oil Engine.— Fig. 211 is a general view 
of Messrs. Fielding & Piatt's oil engine. Fig. 212 is a section 
through the vaporiser, and the admission port to the engine 
cylinder. In this engine the vaporiser and igniter tube are 
combined, a is the vaporiser, b the combined vaporiser and 
igniter tube, c is an air heating tube, and d is a valve com- 
municating between the vaporiser and the igniter tube. The 




Fig. 212. — Fielding & Piatt's Oil Engine (section through vaporiser). 

whole system, a, b, and c, is inclosed within a casing e and heated 
up by means of a lamp f. This lamp is of substantially the same 
construction as the Etna, described at page 431 of this work. That 
lamp has an air reservoir g and an air pump h, and the lamp part 
f is arranged to produce a vapour jet which sucks in by induction 
sufficient air to form a strong blue Bunsen flame. In this engine 
the exhaust and air inlet valves are situated opposite each other, 
opening into the same port. In oil engines this is a highly 
desirable arrangement, because it is advisable to heat the main 
air supply to some extent as it enters the engine, and this is better 
done by causing the air to impinge upon the hot exhaust valve 
and pass through the hot exhaust port before reaching the engine 



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Oil Engines 443 

cylinder. To start the engine the lamp is ignited and the igniter 
tube, vaporiser tube, and air tube are heated up. Oil is then 
injected by means of a small suction pump and discharged by 
the jet a into the vaporiser a ; on the suction stroke of the engine 
the air valve 1 opens, and air is drawn into the engine cylinder. 
At the same time air passes by means of a small air inlet 
aperture k through the air heating tube c to the chamber b, and 
thence to the vaporiser tube a. The valve b is opened by a cam 
during the suctipn stroke, and the air and vapour pass together 
through the igniter tube b into the cylinder. The charge of oil 
is thus sucked through at each stroke and taken into the engine 
cylinder by a small quantity of air, there to mix with a larger 
quantity of air already in the cylinder. The port l is somewhat 
large, and it becomes hot by the exhaust gases and by the 
explosion, and so maintains the vapour without condensation as 
it enters the cylinder. 

An engine was exhibited by Messrs. Fielding & Piatt at the 
Cambridge Show. Its dimensions were — diameter of cylinder 
2>\ ins., stroke 16 ins., weight of engine 53 cwts., declared speed 
170 revolutions per minute. In this engine all the valves, air 
valve, vapour valve, and exhaust valve are actuated from one cam, 
and the governor of the usual hit-and-miss type cuts out explo- 
sions when the engine exceeds its speed by holding open the 
exhaust valve and keeping the air and vapour valves closed. The 
piston thus runs to and fro, taking the exhaust gases into the 
cylinder from the exhaust pipe, and returning them to it again. 
During the trial at the show the lamp Is stated to have given too 
little heat, and consequently rendered the ignitions late. The 
engine ran very steadily, however, and started very readily with 
one attendant only, twenty-two minutes being consumed in 
heating up. As the late ignition could not be remedied at once 
the engine was withdrawn from the test. 

Tests and Oil Consumption. — Messrs. Fielding & Piatt have 
been good enough to send the author particulars of the results ob- 
tained with the engine (see table, p. 444), together with a diagram 
from which fig. 213 has been prepared. The tests and diagram 
show the engine now to be in thoroughly good prder. 

The results are very good indeed ; a consumption of o*8o lb. 



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444 



OH Engines 



of Russoline oil per brake HP hour is superior to that given by 
the first prize engine at the Cambridge Show. 

Tests op a 3 HP Nominal Fielding & Platt Oil Engine 
made by Messrs. Fielding & Platt on November 22 and 23, 1894. 



Power 


Full 


Half 


Light 


Full 


Duration of test 


1 hour 


1 hour 


1 hour 


3 hours 


Revolutions per minute . 


220 


225 


230 


222 


Explosions per minute . 
Nett brake load 


zoo 


84 


18 


100 


63 lbs. 


33 lb ^ 


— 


63 lbs. 


Diameter brake circle 


4 ft. 


4 ft. 


4 ft. 


4 ft. 


Brake HP .... 


5*28 


28 




5 3 


Oil per hour in lbs. (Rassoline) 


475 


1*25 ft). 


*'3 


4-24 


Oil per brake HP hour . 


0*90 lb. 




0*80 lb. 


Available pressure average of 










four diagrams, 79 lbs. 











Fig. 213 is a diagram from a similar 3 HP nominal engine 
taken in a test made on October 22, 1895, which also shows the 
excellent result of *8 lb. of oil per brake HP hour. During that 
test the engine gave 5-5 HP on the brake at 219 revolutions per 
minute, the compression was 40 lbs. and the maximum pressure of 
the explosion was 140 lbs., while the available pressure was 63 lbs. 




Fig. 213.— Fielding & Piatt's Oil Engine (diagram). 

Messrs. Fielding & Platt state that ten minutes suffice for the 
heating of the igniter and vaporiser, and that having started the 
lamp it is only necessary for the driver to go round the engine 
and examine and fill up lubricators ; after this the vaporiser will 
be hot enough, and on giving the fly-wheel a turn or two the 
engine starts. A half compression cam is provided to ease the 
starting. 



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445 



This engine is extremely simple, and the timing valve is 
entirely dispensed with, the igniter tube b being at all times open 
to the cylinder. The engine is exceedingly economical at light 
loads as well as at full load. 




Fig. 214.— Campbell Oil Engine (section through vaporiser and igniter), 

Campbell Oil Engine.— The Campbell engine resembles the 
Tangye engine in its vaporising arrangements. There are only 
two valves, inlet and exhaust ; the air inlet is automatic and the 
exhaust is operated in the usual manner. In this engine also there 
are no oil pumps ; the vaporiser is fed by gravity, and so is the 



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Oil Engines 



lamp. Ignition is produced by incandescent tube, and the 
vaporiser and tube are heated by a lamp. The engine resembles 
the Tangye in passing the whole of the air charge through the 
vaporiser to carry off the vapour when formed. Fig. 214 is a 
section through the vaporiser arid igniter tube of the Camp- 
bell oil engine. Fig. 215 is a horizontal section showing the 
exhaust valve and the end of the vaporiser. Fig. 216 is a side 




Fig. 215. — Campbell Oil Engine (horizontal section through exhaust valve). 



elevation of the end of the engine, showing the operation of the 
governor. 

An automatic inlet valve a serves for admission of the whole 
air charge to the cylinder by way of the vaporiser b and passage 
G. The oil is fed by gravity and passes through the supply pipe 
c to an annular channel d round the seat of the valve a, and is 
injected through perforations e to mix with the air when the valve 



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447 



opens. This valve, like the Tangye, resembles the gas and air 
valve first introduced by Clerk. On the suction stroke of the 
engine, air enters by the valve a, and oil entering with it is carried 
through the vaporiser, and the mixture of inflammable vapour and 
air passes into the engine cylinder by the passage g ; this passage 
g leads into the exhaust port, as clearly seen at fig. 215, and thus 
one port serves for the admission of the charge to the cylinder and 
the discharge of the exhaust products. The igniter tube h is 




CEral 



Fig. 216.— Campbell Oil Engine (side elevation of cylinder end). 



screwed into the bend of the vaporiser and is always in open com- 
munication with it. The lamp which heats the tube also heats the 
vaporiser, but while at work the heat of the explosions is sufficient 
to keep up the vaporiser temperature. The explosion ensues 
upon compression, the inflammable mixture being forced into the 
hot tube. This engine, however, is found to ignite without the 
tube after running for some time. 

The governing is accomplished by a ball governor 1, fig. 216, 
which controls the exhaust valve j. This valve is opened at every 



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448 



Oil Engines 



exhaust stroke by the sliding piece k, which at one end of its stroke 
strikes the pin l, and by moving the lever m opens the exhaust 
valve. When the engine speed rises above normal the governor 
sleeve rises and moves the lever n and link o ; this interposes the 
small plate p between the outer end of the lever m and the stationary 
bracket Q. The exhaust valve spring is thus prevented from 
pulling the valve back to its seat until the speed falls again. The 

lb. per ISa in 
absolute 



200 

ISO 

160 

l+O 

tzo 
too 

80 

eo 

40 
20 






























































































































































































































































































































a 



































./ -2 v> .* 

Fig. 217.— Campbell Oil Engine (diagram). 

holding open of the exhaust valve j thus prevents the suction 
of a charge of oil and air through the automatic valve a. This 
engine, like the Tangye, is very simple, but in the author's opinion 
the oil fed by gravity is troublesome, and in all but small engines 
is also likely to be dangerous. 

Tests and Oil Consumption. — A Campbell engine was tested 
at the Cambridge Royal Agricultural Show. The engine was de- 
clared as of 6 HP nominal, the diameter of the cylinder was 7^ ins., 



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449 



and the stroke 1 2 ins. The declared revolutions were 240 per 
minute. The engine weighed 27 cwts. In a three days* test it 
gave 475 brake HP on an oil consumption of 115 lb. Russoline 
oil per brake HP. In a subsequent full power test the engine gave 
481 brake HP, and indicated 5*9 horse on a consumption of '93 
lb. of oil per I HP per hour, and 1*12 per brake HP per hour. 
The average speed during the trial was 2077 revolutions per 
minute, and the average pressure developed in the cylinder was 
65-5 lbs. Fig. 217 is a dia- 
gram taken from the Camp- 
bell engine during a two hours' 
test. The Campbell ran with- 
out load at 2 1 1 revolutions per 
minute on a consumption of 
2*32 lbs. of oil per hour. 

Britannia Oil Engine, — 
The Britannia engine is the 
invention of Mr. Roots, and in 
it also the air heater, vaporiser, 
and incandescent tube are 
neatly combined in one cast- 
ing. The oil feed arrangement 
too is ingenious, and dis- 
penses with a pump of the 
ordinary type. Fig. 218 is a 
section showing the air heater, 
vaporiser, and ignition tubes, 
as also the air inlet valve of 
the engine. Fig. 219 is an 
end elevation part in section 
showing the action of the oil 
feed. Oil is fed to the oil bath 
stant level in that bath by the 




Fig. 218.— Britannia Oil Engine 
(section through vaporiser). 



a, fig. 219, and is kept at a con- 
overflow hole a. A spindle b is 
reciprocated to and fro by the levers c, d, and a cam e on the 
valve shaft f. The governor lifts the lever g, carrying the trip 
piece h, shown in dotted lines, and so long as this trip piece is 
held opposite the operating edge of the lever d, the spindle is 
moved. When the governor lifts the trip piece the spindle b 

g G 



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45o 



Oil Engines 



remains stationary. Grooves b are cut round the spindle b ; 
these grooves fill with oil, and on pulling the spindle b through 
to the chamber i the oil falls off or is blown off by the passing air. 
This chamber is seen at i in fig. 218 as well as in the end elevation. 
The upper part of that figure shows a spiral or louvre deflecting 
plate device, forming part of the casing k ; air enters at the upper 
part, passes over the deflecting plates which are heated by the 
flame, serving to heat the ignition tube l. The ignition tube l is 
placed in a circular casing, the upper part of which carries the 




m* 



Fig. 219. — Britannia Oil Engine (oil feed and governing). 

deflecting plates referred to, and the lower part carries the 
vaporiser m. The air enters the engine by way of the deflecting 
plates, passes over them, and becomes heated, then strikes upon 
the oil supply spindle b and removes the oil from the grooves, 
carrying it into the vaporiser, and then carrying the oil from the 
vaporiser m to the air inlet valve n, and thence by the inlet port o 
to the engine cylinder. Ignition is caused at the proper time by 
the compression of the combustible mixture into the hot ignition 
tubei*. 



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451 



The lamp used in the Roots engine is shown at fig. 220, which 
is an elevation part in section. It is of the now standard type 
like the Etna, and consists of a tube a bent round upon itself to 
form an elongated loop. At the end b of the loop is arranged a 
small opening c, in which a conical pin d fits. The point of the 
pin projects through the small hole e, and so forms an adjustable 
annular orifice. An oil vessel f is connected to the tube a, and 




Fig. 220.— Britannia Oil Engine (lamp). 

has attached to it a small air pump g. Outside the bent pipe a 
is a sleeve or hood h open at both ends. 

To start the lamp the tube a and hood h are first heated by 
a piece of waste soaked in oil and lighted. Air is pumped into 
the reservoir f by means of the small air pump g until the oil is 
forced through the asbestos 1 contained in the tube ; the oil heats 
and boils off, discharging as a strong jet at the annular orifice 

G g 2 



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Oil Engines 



made by the pin d. The jet is lit and the name heats the bent 
tube and is discharged out of the hood h as a fierce blue smoke- 
less name. 

This lamp is similar to the others, but the small points of detail 
peculiar to it are interesting. 

The Britannia engine, like the Tangye and Campbell, takes in 
the whole air charge through the vaporiser. 

Tests and Oil Consumption. — One of the Britannia engines was 

lb. per Sain 



ZOO 

/so 

/60 
MO 

tzo 
too 

80 
60 
40 
















































K 




















\ 




















fl 


s, 


















\l 


\ 


















// 




v 
















'J 




N 


S^ 














\ 






^» 


^ 


^-^ 


^ 


20 





















O 





















V '1 * + yf 

Fig. 221. —Britannia Oil Engine (diagram). 

tested at the Cambridge Show ; its dimensions were — diameter of 
cylinder 7| ins., stroke 13 ins., declared revolutions per minute 235, 
weight of engine 33 cwts., declared power 7 brake horse. On a 
three days' test the engine developed on an average 6*15 brake 
horse and consumed 1*49 lb. of oil (Russoline) per brake 
horse hour. On the subsequent full power test, lasting for two 
hours, the engine gave 6*21 brake HP and indicated 84 HP. 
Running at 240 revolutions per minute and giving a mean effec- 
tive pressure of 47*3 lbs. per sq. in., the oil consumed was 



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Oil Engines 453 

1-25 lb. IHP hour, and i*68 lb. per brake HP hour. On half 
power the engine developed 3-96 brake horse, consuming 1-67 lb. 
per brake horse hour. Running light without load the engine 
made 256 revolutions per minute, and consumed 1*44 lb. of 
Russoline oil per hour. It is a somewhat remarkable fact that 
this engine, which consumed the largest amount of oil per HP 
of any of the engines tested at the Cambridge Show, ran with 
no load at full speed on the lowest consumption of oil of any. 
Fig. 221 is a diagram from this engine taken during the two 
hours' trial. In the trials this engine was found to require 12 and 
13 minutes to start ; on one occasion however it took 24^ minutes 
to heat up for starting. 

Clarke, Chapman &* Co.'s Oil Engine. — A vertical longi- 
tudinal section of this engine is shown at fig. 222, and a 
transverse section at fig. 223. The engine is peculiar among 
petroleum engines in dispensing entirely with lift valves and 
depending for all the operations of the engine upon a rotating 
plug valve. This valve is rotated by a shaft driven at one fourth 
of the speed of the crank shaft, and by its rotation the whole of 
the operations of admission and exhaust are performed ; the 
ignition is obtained by means of the electric spark. Although the 
vaporising and valve actions of this engine present externally a 
simple appearance, yet internally they are extremely complex, too 
complex in the author's opinion to be suitable for the rough con- 
ditions of public use. a is the plug valve rotated as described by 
the valve shaft b. The port a 1 through the valve is the exhaust 
port which connects by means of another port a 2 with the exhaust 
pipe, a 3 is one of the air and charge inlet ports communicating by 
means of a port a 5 with the air supply passage c opening through 
the throttle valve d to the mixing chamber for air and vapour e. 
The exhaust discharges by the pipe f round the conical vaporising 
chamber g and out at the exhaust pipe f'. The air supply is also 
heated by the exhaust gases, and an air jacket is formed round the 
exhaust pipe at h. The air, when heated, passes by way of the 
passage 1 into the mixing chamber e, and the oil, which is forced 
from the oil supply reservoir k by air pressure into the vaporiser, 
is vaporised and passes into the mixing chamber by way of a 
similar passage l, and there mixes with a further portion of hot 



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Oil Engines 455 

air. A small portion of air passes through the vaporiser to 
carry off the oil vapour, and this portion of air is heated also by 
the exhaust gases. The engine is governed by throttling the 
charge admitted by means of the throttle valve d operated from 
the governor shaft m, and at the same time the oil supply is varied 
with the air supply. This method of governing is not a good one, 
and must result in a somewhat high consumption at light loads. 
The difficulties too of maintaining the working surfaces of a plug 
valve under the trying conditions operating in a gas engine have 
prevented plug valves being used to any extent except for the 
very smallest engines. The author is somewhat surprised that 
the inventor of this engine (Mr. Butler) should have attempted to 
use a plug valve under the vastly more difficult conditions of a 
petroleum engine. To start the engine a small quantity of 
benzoline is used, which is supplied until all the parts are heated 
up sufficiently. An engine of this type was exhibited at the 
Cambridge Show ; it was rated at 6 HP brake, the diameter of 
the cylinder was 7^ ins., and the stroke 12^ ins. The speed was 
declared to be 350 revolutions per minute. The weight of the 
engine was 35 cwts. Owing to difficulties with the engine at the 
Show, however, it was withdrawn from competition. 

Weyman 6° HitchtocKs Oil Engine. — This engine resembles 
the Hornsby and Robey engines in that the vaporiser is heated 
by the heat of the explosions and exhaust products only. In it, 
however, the gases are ignited by an incandescent tube raised to 
incandescence by a separate lamp. The vaporiser chamber, 
however, communicates with the cylinder by a valve, and so the 
engine comes under this particular head. The oil supply is 
pumped through a sight feed tube d to the top of the vaporiser, 
as shown at fig. 224, where d is a sight feed tube and c the 
vaporiser. This oil with a small proportion of air passes round 
an annular passage, and the oil gradually vaporises as it falls and 
diffuses into the air accompanying it. The oil charged with 
vapour rises through a series of holes to a central chamber and 
then passes through a vapour valve into the cylinder, where it 
meets with an additional air supply. The ignition tube is heated 
by an external lamp operated by a powerful air blast produced 
from an air pump on the engine. Fig. 225 is an end elevation of 



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Oil Engines 



this engine duly lettered with references printed underneath. 
From this it will be seen that the engine is of somewhat complex 
construction . 

Tests and Oil Consumption. — An engine exhibited at the 
Cambridge Show was declared as of 5 brake HP, the cylinder 
was 6 J ins. diameter by 13 ins. stroke, and the declared speed 
was 250 revolutions per minute. On a three days' test the engine 
developed a mean power of 6*21 brake horse and consumed 
1 '13 lb. of oil per brake horse hour. The engine took from 14 
to 17 minutes to start. At a full-power test lasting for two hours 




Fig. 224. — Weyman & Hitchcock's Oil Engine (part section). 

a, cylinder ; b, combustion chamber ; c, oil inlet ; p, sight feed tube ; e, pump ; 
f, main air supply ; i, lubricator. 

the same engine developed 6-5 IHP, 473 brake horse on a mean 
speed of 2597 revolutions per minute, and consumed '87 lb. 
of oil per IHP hour, and 1*19 lb. per brake HP hour. At 
half load the engine developed 2*58 brake horse ; the oil 
consumed was 1*57 lb. per brake horse hour. Running without 
load at 207 revolutions per minute the engine consumed 277 lbs. 
of oil per hour. Fig. 226 is a diagram from the engine. 

Wells Brother? Oil Engine. — Fig. 227 is an end elevation of 
the Wells engine, showing the important parts. Professor Capper, 



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457 



in his report to the Royal Agricultural Society, describes it as 
follows : 

c There is but one rocking lever to actuate all the valves. It 
is driven by a cam on the lay shaft, in opposition to a powerful 
spiral spring. When running at normal speed, the spring draws 
the lever home, closing the exhaust valve, and opening the vapour 




Fig. 225.— Weyman & Hitchcock's Oil Engine (end elevation). 



a, side lever i 



inlet 
air 



e lever '<:, governor ; de, rocking levers working oil and air valves ; f, air 11 
pipe ; Q, oil reservoir for lamp ; R. oil supply pipe to lamp ; s, air blast pipe ; t, air 
pump ; u, lamp reservoir ; w, oil pump ; x, oil pump discharge ; y, oil supply 
pipe ; z, pet cock. 



valve at the required moment. When running too fast, the hori- 
zontal catch, which has been lowered, by the outward movement 
of the valve lever, has not time to rise clear under the weight of 
its inner end before the return of the vertical lever, which there- 
fore is arrested, and no movement of the valves takes place. 
The exhaust valve is then kept open, and the vapour valve being 



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458 



Oil Engines 



closed, an idle stroke occurs, the oil valve at the same time emit- 
ting a charge from the vaporiser. The oil valve is a rotating taper 
plug, driven by a link off a rocking lever. A cavity in this plug 
measures out a charge of oil at each vibration, and drops it upon 
a heated diagonal plate, down which it runs and is vaporised An 
adjustment is provided by which the quantity of oil at each charge 
can be regulated, and the valve box is filled by gravity from a 
raised tank. This arrangement is secure against injury from dirt, 
as anything that is small enough to pass into the oil plug would 
simply fall to the bottom of the vaporising chamber, and there 

lb. pep Sf. in. 
aisolutc 

/60 
i+0 
iZO 
iOO 

so 

60 



20 



i * -a * 

Fig. 226. — Weyman cS: Hitchcock's Oil Engine (diagram). 

be retained. The lamp which heats the vaporiser is completely 
inclosed in a cast-iron combustion chamber, the blast being sup- 
plied by an air pump.' * The makers claim that little, if any, 
gasification takes place, as the vaporiser is water- jacketed, and so 
not overheated. This view is to some extent upheld by the fact 
that the cylinder works without lubrication, beyond that of 
inclosed oil vapour/ 

Tests and Oil Consumption. — An engine of this type was 
exhibited at the Cambridge Show of a declared 4 HP nominal. 
The cylinder was 8^ ins. diameter, and 15 ins. stroke, the declared 



n 


> 


^, 


^v 


1 ^y^ 




"^^■^■^ JJ 


1 ... . . 



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Oil Engines 



459 



speed being 165 revolutions per minute. This engine gave on the 
three days' test a mean power of 5-96 horse, and consumed ro6 
lb. of oil per brake horse hour. The engine was very easily 
started, starting usually in from 10 to 17 mins. A full- power test 
of two hours gave an indicated power of 7*3, and a brake power of 
646 horse, the oil consumption being -93 lb. per IHP per hour 
and 1 -04 per brake horse hour. The engine ran at an average 
speed of 184 revolutions. 
At half-power 3*52 brake 
horse was given, and a 
consumption of 1*59 lb. of 
oil per brake horse. Run- 
ning without load the en- 
gine used 1 "96 lb. of oil per 
hour at 165 revolutions per 
minute. Fig. 228 is a dia- 
gram taken from the Wells 
engine. 

Applications of Petro- 
leum Engines.— Petroleum 
engines have now been 
applied, in addition to the 
ordinary purposes for which 
stationary engines are re- 
quired, to the propulsion 
of launches, and for ac- 
tuating road carriages. Most 
of the launch engines use 
gasoline or other light oil, 
and so present no peculia- 
rities which need be studied here 




vapour valve ; c, horizontal catch : d, vaporiser 
'door ; e, exhaust valve ; k, trip ; l. rocking lever: 
m, oil supply cock ; n, oil supply chamber ; o, oil 
supply pipe ; v, oil supply to lamp ; q, automatic 
explosion counter ; R, link working oil valve ; v, 
vaporiser. 

Fig. 227.— Wells Oil Engine 
(end elevation). 

von^i t«=*.** — ~v™~- It will be observed that the 

au^hTs ^described any of the oil engines produced on the 
Continent or in America. These engines are without exception 
engines of the ordinary gas engine type using gasoline or other 
light oils which require no special precautions, and indeed are not 
interesting as bearing on the question of safe heavy oil engines. 
The engines on the Continent and in America which use heavy oil 
are those already described in this chapter or engines following 



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Oil Engines 



the same lines. Many ingenious details are used in the foreign 
oil engines, but as yet British inventors appear to have taken the 
lead in the task of devising means of utilising the safe lamp oils 
of commerce. This probably is due to the somewhat severe legal 
restrictions placed upon the sale and storage of such light and 
inflammable oils as gasoline, benzine or petroleum spirit, restric- 
tions which do not exist in the laws of America or France. The 
principal engine used upon the Continent for marine purposes is 
that of Daimler. 

The Daimler engine is a small two-cylinder engine ; the two 

l&perSa.hru 






too 




•/ •* 3 * ar * 

Fig. 228.— Wells Oil Engine (diagram). 

cylinders incline at an angle of about 30 to each other, and the 
connecting rods operate on a common crank pin. The front ends 
of the cylinders are closed in, and the front ends act as air pumps. 
The Otto cycle is performed by each piston, but each cylinder is 
supercharged with air to a pressure of a few pounds above 
atmosphere, the air being supplied from the front of the piston. 
By this device a high average pressure is obtained, but light oil is 
used so that no special vaporising arrangements are required. 

The Daimler Motor Carriage. — The Daimler motor carriage has 
come into considerable prominence in connection with the recent 
trials of horseless carriages in France. The author has carefully 



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Oil Engines 461 

examined one of these carriages, and finds that it contains one 
of the ordinary two-cylinder Daimler light oil motors, which is 
mounted with its crank shaft axis parallel to the length of the 
carriage. The engine is started by a handle projecting from the 
front of the carriage, which handle drives a spindle by pitch chain. 
When the engine starts, it puts a stop out of gear and disconnects 
the chain. The engine shaft gears into a friction clutch, which 
can be drawn in and out to disconnect the engine from the 
carriage wheels. The back wheels of the four-wheeled carriage 
are driven by a shaft carried across the centre of the carriage, and 
operated from the engine-driving spindle by bevil wheel and 
opposing bevil wheels so geared as to form a reversing arrange- 
ment by engaging on one or other side of the engine bevil wheel. 
The spindle carrying the engine bevil wheel is geared to the 
engine shaft by means of change wheels of the ordinary pinion 
and spur wheel type, four sets of wheels being provided which 
may be geared one pair at a time to give four different speeds 
without varying the speed of the engine. The two front wheels 
are steering wheels, and are operated by a lever somewhat like 
that used to steer a Bath chair. The rear driving wheels of the 
carriage are geared to the cross shaft by pitch chains. The en- 
gine uses light oil contained in a small reservoir in front of the 
driver. The mixture is ignited by means of two platinum tubes 
heated to incandescence by an oil flame of the Bunsen type. The 
engine when started runs at a constant speed, and the whole of 
the operations of the carriage are performed by means of levers, 
clutches, change wheels and brakes. In the author's opinion 
this carriage, ingenious as it is, will not find much use in England. 
A carriage, however, using heavy oils and overcoming the diffi- 
culties would probably be very successful. 



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462 Oil Engines 



CHAPTER III. 

THE DIFFICULTIES OF OIL ENGINES. 

The reader will have observed from the description of thirteen 
different examples of oil engines given in the preceding chapter, 
and the details of oil consumption and efficiency, that the oil 
engine is not so economical from a heat engine point of view as a 
gas engine ; that is, the oil engine so far, for a given number of heat 
units entrusted to it as oil, does not convert so large a proportion 
of those heat units into indicated work as a gas engine. It is to 
be remembered, of course, that as yet engineers have had little 
experience in oil engines as compared with gas engines, and that 
probably with further development of detail the heat efficiency of 
the oil engine may yet be considerably increased. The lower 
efficiency at present obtained is due to certain difficulties peculiar 
to the oil engine, which do not occur in the gas engine. These 
difficulties are present to some extent in all the three types of 
engine, but in some types to a greater extent than in others. In 
the earlier engines ignition presented a formidable difficulty, which 
was overcome by the use of the electric spark. Electric methods 
of ignition are very objectionable whether used in gas or oil 
engines ; so objectionable, indeed, that no gas engine at present 
manufactured in Britain uses an electric igniter. Electric igniters 
require a battery, an induction coil and insulated points, or an 
electro-magnetic device, and insulated points with a contact- 
breaking contrivance. Either of these forms can be made to work 
quite well in an engineer's hands or in the hands of anyone used 
to batteries and dynamos, and willing at the same time to devote 
considerable attention to keeping the apparatus in order. The 
public in this country, however, who use gas and oil engines are 
very liable to allow electric contrivances to get out of order, and it 



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Tfie Difficulties of Oil Engines 463 

has always been the author's opinion that any engine with an 
electric igniting device, even if good in other respects, would not 
attain extended use in Britain. Curiously enough this objection 
does not seem to weigh much with the Continental public or with 
the American public, as many engines are sold on the Continent 
and in America which use electric igniting devices. The nature 
of safe burning oil made it very difficult to use either a flame 
device for igniting or an incandescent tube for that purpose. It 
was by no means easy and evident to see in what way safe heavy 
oil could be treated to give a smokeless heating flame of the 
character necessary either for flame ignition or incandescent tube 
ignition. The production of the type of lamp described at 
page 431 gave, however, an easy means of producing a smokeless 
heating flame, and so at once made it possible to use that simplest 
of all igniting devices, the incandescent tube. In the author's 
opinion the incandescent tube igniter is by far the best adapted 
both for oil and gas engines, and now that simple lamps have 
been produced to give a smokeless flame the incandescent tube 
is bound to displace all other forms of ignition for oil engines. 
The type of lamp referred to also seems to the author to be the 
best yet proposed, as it gives a powerful smokeless flame from 
heavy oils, and that without the use of the troublesome air blast. 
In many of the earlier forms of the engines described, an air 
blast was used somewhat in the manner shown at fig. 194 and 
described as the Griffin oil sprayer lamp. So far, then, as the 
present engine is concerned, the difficulty of igniting may be con- 
sidered as thoroughly overcome in a manner which is not likely to 
be greatly improved upon, and so far as the ignition is concerned 
there is nothing which prevents greater economy from being 
obtained. The difficulties which prevent immediate improvement 
in economy are to be found in all cases in the methods of vapo- 
rising. Some inventors claim to gasify wholly or partly the oil 
which is sent into the engine cylinder, and others claim that the 
oil so sent in is merely vaporised and not gasified. The author 
has examined all the standard types of oil engine now in use, and 
from his own experiments he is convinced that in not one of the 
engines does any real gasification take place ; in all the thirteen 
engines referred to the oil is vaporised, not gasified. In some of 



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464 Oil Engines 

the engines the oil may be ' cracked ' to a small extent, so that 
the vapours produced are those of lighter hydrocarbons than were 
present in the original oil, but no cracking which can take place 
in any of these engines is anything like sufficient to carry decom- 
position far enough to produce gas instead of vapour. 

These engines have been classified by reference to the method 
of vaporisation peculiar to each, and each type, although it 
presents a satisfactory solution of the vaporising difficulty, in- 
volves additions to the ordinary gas engine cycle which are 
accompanied by characteristic limitations or disadvantages. 
Thus the first type of oil engine using safe oil, 'engines in 
which the oil is subjected to a spraying operation before 
vaporising,' is also first in the order of invention, and it naturally 
presents the most complex solution of the vaporising difficulty. 
In this type of engine, represented by the engines of Messrs. 
Priestman and Samuel son, the whole air supply of the engine is 
passed through a heated chamber, and according to Professor 
Unwin, in one of his tests, the air leaving this heated chamber 
before it enters the engine cylinder is raised to a temperature of 
287 F. The chamber is heated by the exhaust gases from the 
engine, which gases in this experiment were at a temperature of 
6oo° F. ; the oil to be vaporised is injected into the heating 
chamber, by means of a smaller quantity of air, in a state of very 
fine spray, as has been described in the preceding chapter. The 
whole of the oil used is therefore mixed with the air passing 
into the engine in minute particles of spray, each of these minute 
particles of sprayed oil being surrounded by an atmosphere of air 
at a temperature of nearly 290 F. Each oil particle thus has an 
ample atmosphere of air surrounding it at this high temperature, 
and thus each particle rapidly evaporates and passes from the 
state of spray to the state of oil vapour uniformly diffused 
throughout the air charge. The device produces very perfect 
vaporisation, but it has the great disadvantage that the whole of 
the inflammable charge entering the cylinder becomes heated to 
290° F. while still at atmospheric pressure. From this it follows 
that upon compressing the mixture in the cylinder the temperature 
of compression rises to a much higher point for a given pressure 
than is the case with a gas engine charge working at that pressure. 



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The Difficulties of Oil Engines 465 

In the gas engine the charge enters the cylinder at atmospheric 
temperature, and is only heated to a slight extent by the inclosing 
walls. In the case of the oil engine the entering charge is heated 
to begin with, and is likely to absorb further heat from the piston 
as it enters. This has the effect of reducing the total weight of 
charge present in the engine cylinder at each stroke, and therefore 
it reduces the average available pressure to be obtained from the 
engine. In the Priestman engine, for example, the best result 
obtained in Professor Unwin's experiments give only a mean 
available pressure of 45 lbs. per square inch throughout the stroke 
with a compression pressure of 27 lbs. It is worth noting that a 
compression pressure of 27 lbs. was used in a Priestman engine at 
a time when the usual compression pressure in gas engines ranged 
from 40 to 50 lbs. This low pressure necessarily involves less 
economy than the high pressure, and the reason why a low pressure 
is adopted is found in the fact that at higher pressures an oil engine 
operating by the spray method is very liable to premature ignitions. 
This is partly because of the ready inflammability of a mixture of air 
and heavy oil vapour, and partly because of the higher tempera- 
ture of compression due to the preliminary heating of the whole 
charge in the vaporiser. An oil and air charge is much more 
liable to spontaneous ignition during compression than a gas and 
air charge, and the preliminary heating of the whole charge to 
about 8o° F. above the boiling point of water necessarily increases 
the temperature obtained by compression, and this higher tem- 
perature tends to make the charge ignite prematurely. 

It is interesting to note that with Daylight oil Professor 
Unwin found a pressure of compression of 35 lbs. per square inch 
more suitable than 27 lbs. This is doubtless due to the fact 
that lighter oils such as Daylight oil when vaporised approxi- 
mate more nearly to the gaseous condition, and are therefore less 
easily subject to premature ignition than the heavier oils. 

One difficulty, therefore, caused by the spray method of 
ignition lies in the limitation of the weight of the charge by pre- 
liminary heating, from which follows the production of a lower 
average pressure ; another difficulty lies in the limitation of the 
compression pressure due to the property of spontaneous ignition, 
which is made more marked by the preliminary heating. These 

H H 



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466 Oil Engines 

difficulties prevent the attainment of greater economy by the first 
method of vaporising. 

This method, however, presents other difficulties of a practical 
kind. Thus a large volume of charge is formed in the vaporiser 
in explosive proportions, and the whole of this charge is liable to 
be ignited in the event of a back explosion from the engine 
cylinder while the charging stroke is proceeding. This is a 
serious difficulty, and has caused in gas engines the practical 
abandonment of all engines in which a reservoir of gas and air 
is used to feed the engine cylinder. 

A further difficulty occurs in governing the engine. As the 
exhaust gases are used to heat the vaporiser, by means of a 
jacket surrounding the vaporiser chamber, it follows that the 
ordinary method of governing practised in the gas engine is 
inapplicable. Messrs. Priestman accordingly produce ignitions 
under all circumstances, whether their engine be light or loaded ; 
that is, instead of cutting out impulses by stopping off the oil 
supply completely, they reduce both oil and air supply simul- 
taneously, and by so doing reduce the pressure at which the 
cylinder is filled with inflammable mixture before compression 
begins. The proportion of oil and air admitted is kept as nearly 
as possible constant, but the compression pressure is continuously 
reduced and produces weaker and weaker impulses. This is 
clearly shown in the diagram, fig. 191, page 417, where the full-power 
diagram is shown by a heavy black continuous line, the half- 
power diagram by a dotted line, and the diagram produced when 
the engine is running light by a thin full line. This method is by 
no means an economical one, and results in a heavy consumption 
of oil even at light loads. In Professor Unwin's test, for example, 
it was found that the engine consumed 6\ lbs. to 7 lbs. of oil per 
hour when working at full power ; and when working giving no 
power at all, only driving itself at full speed, the oil consumption 
was still 5 lbs. This of course is a very poor result, the engine 
using almost as much oil without load as at full load ; in fact in 
Un win's test there was no difference in oil consumption between 
half power and no load at all. This is a difficulty, however, 
which is common to all gas engines as well as oil engines in which 
the charge is supplied from an intermediate reservoir of consider- 



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The Difficulties of Oil Engines 467 

able capacity. With such a reservoir it is evident that the govern- 
ing cannot be effected by simply cutting off the gas supply, as 
if the governor had acted the engine would still receive one or 
more charges and give one or more impulses after the governor 
had signalled that it was running too fast. In the same way, 
when the governor put the gas or oil supply on fully again, the 
engine had to make several revolutions before the mixture reached 
the cylinder. This causes serious irregularity as well as loss of 
gas due to imperfect mixture at the time of governing. 

Messrs. Samuelson endeavour to avoid this difficulty of governing 
by holding closed the exhaust valve, and keeping the inlet valve 
closed. In this way the piston expands and compresses the ex- 
haust gases without taking any charge from the vaporiser. This 
method of governing, however, is not satisfactory, because of the 
difficulty of keeping a constant charge in the vaporiser while 
the engine is governing. A further difficulty is due to the fact 
that when the explosions cease exhaust gases no longer pass 
round the vaporiser, and the temperature rapidly falls, so that it is 
liable to get much too cool for the effective performance of its 
work. This difficulty affects the Priestman engine to a lesser 
extent because of the continuance of the explosions, but even 
there the temperature of the vaporiser falls considerably when 
the engine is running with light loads or no load at all. 

In the author's opinion the spray method of vaporising as 
hitherto carried out is the least satisfactory of all the methods of 
vaporising, and the second and third methods present consider- 
able advantages over it, both in simplicity and effective operation. 

The second type of oil engine comprises ' engines in which 
the oil is injected into the cylinder and vaporised within the 
cylinder.' The engines constructed under this type repre- 
sented by the Hornsby, the Robey, and the Capitaine engines, 
distinctly advance upon the spray method of vaporising, but they 
also present difficulties of a somewhat formidable kind. The 
Hornsby- Ackroyd engine, for example, tested at the Royal Agri- 
cultural Society's Show gave a mean available pressure throughout 
the stroke of only 29 lbs. per sq. in. This of course necessitates a 
large cylinder for a given power. The mean pressure, it will be 
observed, is lower than that given by Class I., and this although 

h 11 2 



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468 Oil Engines 

the compression pressure is much higher. The Hornsby engine 
gave a compression pressure of 50 lbs. per sq. in, and should have 
given a higher average pressure than that of Class I. but for 
certain peculiarities which have now to be considered. In this 
type of engine the walls of the combustion space are allowed to 
attain a temperature of nearly 8oo° C, sufficient to cause effective 
vaporisation and also to allow of ignition when compression is 
completed. The air charge entering the cylinder in the Hornsby 
engine does not pass through the combustion space, but passes 
directly into the water-jacketed cylinder. The air, therefore, is 
not heated up by passing through the vaporising chamber ; the 
exhaust gases of the previous explosion, however, are kept at a very 
high temperature in the combustion chamber, which chamber 
is cut off to a certain extent from the main cylinder by the 
bottle neck seen at fig. 195, page 421. The cause of the low 
available pressure, however, is not due to heating of the air while 
entering, the cylinder, as that heating only occurs to a slightly 
greater extent than in the case of the gas engine. The real cause 
of the low average pressure is imperfect mixing of the air charge 
with the oil vapour. The oil is injected into the combustion 
space a during the charging stroke of the piston. It rapidly 
evaporates because of its contact with the highly heated walls, 
and it diffuses among the hot exhaust gases contained in the 
combustion space. As there is, however, very little oxygen pre- 
sent in that space at the moment of vaporising, there is no danger 
of premature ignition. Ignition is not possible until air has been 
forced from the cylinder through the bottle neck to supply 
oxygen sufficient for the combustion of the vaporised oil. As the 
compression proceeds, more and more air mixes with the vapo- 
rised oil, and sufficient oxygen is forced into the combustion 
chamber to properly burn the oil vapour charge. A certain 
amount of oxygen, however, and nitrogen remains outside the 
combustion chamber in the space between its limits and the 
piston, and so the cylinder is not filled with a uniform inflam- 
mable mixture. The mixture produced within the combustion 
chamber is also less perfectly mixed with the air than the charge 
in a gas engine cylinder, and accordingly to insure complete com- 
bustion of the whole charge, a much larger proportion of oxygen 



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The Difficulties of Oil Engines 469 

is necessary than in the gas engine. The average pressure of the 
explosion is thus considerably reduced. 

The reduction of average pressure would not matter much if 
the only requirement were a larger diameter of cylinder ; that is, an 
increased diameter without corresponding increase of the strength 
of the crank, connecting rod, and engine frame ; unfortunately, 
however, in the case of an oil engine or a gas engine the effect of 
a double charge has always to be well kept in mind. Such a 
double charge would raise the maximum pressure to an unsafe 
point for a given diameter of cylinder unless the parts were made 
sufficiently strong to resist this possible contingency. In the oil 
engine, for example, an explosion might be missed and a double 
charge of oil vapour would be left in the cylinder, and so the maxi- 
mum pressure of the next explosion greatly increased. Engines 
of Class II. have, therefore, large cylinders and heavy parts in pro- 
portion to the power developed by them. Their economy also is 
not proportional to the compression pressures used. 

The governing difficulty is also much felt in this type of 
engine. Here it is possible to stop the oil supply and cut out 
explosions just as in the case of a gas engine, but the effect of this 
is to cause the walls of the combustion space to be rapidly cooled 
down at light loads. Most of the engines of this kind work well 
at full or intermediate loads, but at light loads the combustion 
space walls may become so cool that ignition fails and the engine 
stops. Messrs. Hornsby have got over this difficulty to a very 
great extent, but it is a difficulty which is quite formidable in this 
type of engine. If the combustion chamber be so arranged and 
shaped that its walls are sufficiently hot when the engine is running 
without load, they are very apt to be overheated at full loads. 
The skill of the makers of these engines is well shown in pro- 
portions calculated to keep the combustion space walls hot, and 
yet not too hot. 

The fundamental idea of this type of engine is extremely 
fascinating and simple, but considerable complexities arise in 
carrying it into effect, which greatly detract from the advantages. 

In the author's opinion this type of engine will always be 
somewhat heavy and large for the power developed, as it is 
difficult to see how greater average pressures are to be obtained, 



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470 Oil Engines 

or how greater economies are to be expected by reason of any 
modifications of the type. . 

The third type of oil engine comprises ' engines in which the 
oil is vaporised in a device external to the cylinder, and intro- 
duced into the cylinder in a state of vapour.' Engines of this 
class, in the author's opinion, furnish the simplest and most effec 
tive solution of the problems involved in oil engine construction. 
Even this class, however, presents two divisions. The first 
division includes the engines of Messrs. Crossley Brothers, and 
Fielding & Piatt. In these engines oil is injected into a heated 
vaporiser consisting of eicher a series of tubes or a series of 
tubular passages. These tubes or passages are heated by the 
waste heat of the oil lamp used for the incandescent tube. The 
oil is injected at one end of the series of passages together with a 
small quantity of air, and a small further quantity of air is heated 
up by an air heater before reaching the oil ; this hot air passes 
through the vaporiser part of the tubes, and evaporates the oil 
and carries a charge into the engine cylinder in a state of 
vapour. The main air charge enters the cylinder by a separate 
valve, so that only a very small part of the air charge is heated 
and passed in with the oil. By this arrangement the engine 
cylinder itself and all the surfaces in contact with the charge 
are water- jacketed, just as in the case of the gas engine. The 
oil vapour and heated air entering at a port mix with the 
cold air entering at a separate valve, and no doubt some 
little precipitation of the oil vapour will occur because of 
the cold air impinging upon the hot air saturated with in- 
flammable vapour. This precipitation, however, will be in the 
state of very fine mist indeed, and on the compression of the 
charge the rising temperature of compression will speedily cause 
the vapour to be formed again. This method of vaporising has 
the advantage that the air charge is heated up to the smallest 
possible extent consistent with forming an explosive charge by 
means of heavy oil. The compression can thus be increased to a 
greater extent than in the first two classes without danger of 
premature ignition, and so much higher average pressures are 
rendered possible. Accordingly we expect to find a higher 
average pressure in this engine than in the others. Messrs. 



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The Difficulties of Oil Engines 47 1 

Crossley obtained 72 lbs. per sq. in. mean pressure with an ex- 
plosion pressure of 225 lbs. and a compression pressure of 65 lbs., 
while Messrs. Fielding & Piatt obtain a mean pressure of 63 lbs. 
with a compression pressure of 40 lbs. This method of operation 
also has the advantage that it allows of the usual gas engine mode 
of governing, viz. by cutting out explosions. That the governing 
is effective and economical is seen from the fact that a Crossley 
engine which used 9*9 lbs. of Russoline oil per hour, running 
at full load, only used 2*53 lbs. per hour running at full speed 
without load, both figures including the oil for operating the 
heating lamp. The Crossley engine tested was rated at jh HP. 
A 3-horse engine tested by Messrs. Fielding & Piatt, which con- 
sumed 475 lbs. of Russoline oil per hour at full load, ran without 
load on 1 '3 lb. per hour. These results show governing almost if 
not quite presenting the same proportional economy as a gas 
engine. 

The second division includes the engines of Messrs. Tangye, 
Campbell, the Britannia Co., Clarke, Chapman & Co., Weyman 
& Hitchcock, and Wells Bros., and in these engines in all cases 
except one (Clarke, Chapman & Co.) the whole air charge of the 
engine passes through the vaporiser on its way to the cylinder. 
This method of operating as carried out by Messrs. Tangye and 
Campbell has certainly the advantage of great simplicity, but it 
appears to have a disadvantage of less perfect vaporisation than 
is given in the first division. At least a comparison of the oil 
consumption of the different engines seems to point to this. For 
instance the Crossley and Fielding & Piatt's oil engines respec- 
tively consume '82 and '90 lb. of Russoline oil per BHP hour, 
while the Campbell, Britannia, Wells, Weyman & Hitchcock 
engines consume respectively 1*12, i'68, 1*04, and 1*19 lb. of 
oil per BHP hour. The engines of the second division thus 
consume uniformly more oil per BHP hour than those of the first 
division. 

In the author's opinion this is partly caused by the fact that 
the whole air charge is drawn through the vaporiser, and partly 
by the fact that in all of these engines the explosion pressure has 
free access to the vaporiser up to the inlet valve. By drawing 
the whole of the air charge through a vaporiser with no prelimi- 



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472 Oil Engines 

nary heating or only a slight preliminary heating, the temperature 
of the air is so low that it does not assist in any way the vaporising 
of the charge, but rather retards it. As pointed out in Chapter I. 
of this Part of the book, air can only take up oil vapour suffi- 
ciently to saturate it at the particular temperature of the air ; and as 
the tension of oil vapour is very low at the temperature of the 
atmosphere, the air does not really help in vaporising, but 
rather tends to condense the vapour formed by the hot walls of 
the vaporiser. The oil, therefore, which is taken into the 
cylinder is taken in partly as vapour and largely as a somewhat 
heavy spray. This heavy spray readily falls on to the walls of the 
cylinder and produces a less perfect charge. 

The fact of keeping the vaporiser open to the explosion 
right up to the inlet valve has the same effect in an oil engine as 
it would have in a gas engine ; that is, it increases the port sur- 
faces so much as to seriously cool the flame of the explosion 
when the explosion occurs. These two causes are, in the author's 
opinion, the principal causes of the higher consumption of the 
second division of this class. 

To make this type of vaporiser effective the air would require 
to be heated to a considerable temperature before entering the 
vaporiser, and this would of course introduce the difficulties 
which have been already referred to in discussing Class I. A 
valve, it is true, might be placed between the explosion port and 
the tubular or passage port of the vaporiser, and this would un- 
doubtedly improve the economy while running loaded, but it 
would also increase the difficulty of effective governing. This 
type of engine as described is readily governed, and very high 
economies are obtained running without load. To make the 
comparison more readily evident, the author has prepared the 
table on page 473, which contrasts the leading facts connected 
with the three classes of engine. 

Oil Engine Improvements. — The reader must not suppose that 
in the preceding discussion the author is in any way under- 
valuing the great progress which has been made in oil engine 
construction. Greater improvements are to be made in oil 
engines than in gas engines, but inventors are rapidly overcoming 
all the difficulties, and the oil engine of to-day is a very effective 



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The Difficulties of Oil Engines 

Comparison of Oil Engines. 



473 





Class I. | Class II. 

1 


Class III. 
Div. I. 

•82 lb. 


1 Class III. 
Div. II. 


Oil consumption 1 
per BHP hour/ 

Oil consumption I 
per IHP hour J 


'95 lb. 


•98 lb. 


1 • ,„ 

1 113 lb. 


x-68 lb. 


1*04 lb. x'19 lb. 


*861b. 


•8x lb. " 


73 lb. 


•93 lb. 


1*25 lb. 


I 
o'93 lb. , '87 lb. 

i 


Mean available ) 
pressure . . 1 


45 lb. 


29 lb. 


7a lb. 


65*5 lb. 


47*3 lb. 


49 '6 lb. 46'x lb. 


Explosion pressure 


130 lb. 


113 lb. 


925 lb. 


200 lb. 


155 lb. 


135 lb. 1 145 lb. 


Compression } 
pressure . . j 


a; lb. 


50 lb. 


65 lb. 


40 lb. 


45 lb. 

62 BHP 
Britannia Co. 


32 lb. 38 lb. 

1 


Power of engine 


7BHP 


8BHP 


7IBHP 


4"8 BHP 


65 BHP ! 47 BHP 


Name of maker . 


Pries Unan 


Hornsby 


Crossley Campbell 


1 
Wells { Weyman 


Weight 


36 cwt. 


40 cwt. 


32J cwt. J 27 cwt. 


33 cwt. 


36i cwt. 26 cwt, 



and reliable machine. It is idle to deny, however, that further 
improvements are possible, and the author's object is to point out 
the difficulties as clearly as possible in order to aid inventors in 
working on correct lines. Improvements in vaporisers will pro- 
bably take the form of obtaining a very complete cracking of the 
oil, tending to charge the cylinder with vapours of lighter oils 
than those introduced into the vaporiser. This process will 
supply the engine with oils capable of withstanding higher com- 
pressions than are at present used without premature ignitions. 
Every effort will be made also to keep all parts of the cylinder 
cool and water-jacketed as with the gas engine. The heating 
lamp is also capable of improvement, and efforts should be made 
to produce a flame of the Bunsen or smokeless type, giving less 
noise than at present. Oil engine inventors will pay more atten- 
tion to the now well-understood principles of gas engine design, 
and will accordingly do away as much as possible with all long 
ports or increased surfaces in contact with the flame of the 
explosioa 



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APPENDIX I 



Adiabatic and Isothermal Compression of Dry Air. 

[Professor R. H, Thurston, Journal of Franklin Institute, 1884.) 

One hundred volumes of dry air at the atmospheric mean temperature 
of 15-5° C. and 147 lbs. per square inch undergo change of volume 
without loss or gain of heat. The temperatures and volumes corre- 
sponding to various pressures are given. Also the volumes at the 
various pressures if the temperature remained constant at 15*5° C. 



Absolute pressure in 
lbs. per sq. inch 


Temperature of 
compression in 


Volume at 
temperature and 


Volume if 
temperature constant 


Centigrade degrees 


pressures preceding 


at is*5° 


147 


15*5 


IOO -o 




150 


17*26 


9858 


98*00 


20 *o 


42*60 


80*36 


73*50 


25-0 


64*76 


68-59 


5880 


30*0 . 


82*10 


60-27 


49 00 


35 'o 


113*86 


54*oi 


42*00 


40*0 


49*i3 


3675 


45 *o 


12654 


- 45*i8 


3-2-67 


50*0 


138*96 


4193 


2940 


55 


i5o*53 


39*19 


2673 


60 *o 


16138 


36*84 


24*50 


65-0 


171 *6i 


34*8o 


22*62 


70 'O 


181*29 


33*o2 


21-00 


750 


190*49 


3i*44 


19*6o 


800 


199*26 


30*03 


1838 


850 


207-66 


2877 


17*29 


90-0 


21471 


27*62 


l6'33 


95o 


223*45 


26*58 


15*47 


100 *o 


230*91 


25-63 


1470 


1250 


264-66 


2188 


11*76 


150-0 


293*9* 


19*22 


980 


175*0 


3i9*87 


17-23 


8 '40 


200*0 


343*31 


1567 


7*35 


2250 


36471 


14*41 


6*53 


250*0 


411*57 


13*38 


5*88 


300*0 


420*34 


"75 


4*90 


400*0 


480*76 


9*58 


3*9o 


500*0 


53i*2i 


. 817 


294 


600 *o 


574*93 


. 7"i8 


2 45 


700 'O 


60374 


. 6*44 


2*IO 


800 *o 


648*80 


5 '86 


I '84 


900*0 


68o*86 


5*39 


I 63 


IOOO 


71049 


500 


i*47 


2000 


929*67 


3*06 


074 



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4 76 



The Gas Engine 



Analysis of Coal Gas. 
{T. Chandler, Watts' • Diet' Sttpp. 3, Part 1.) 





Heidelberg 


Bonn 


Chemnitz 


London 










Ordinary 
coal gas 


Cannel 
gas 




vols. 


vols. 


vols. 


vols. 


vols. 


HydTogen, H . . 


44-00 


3980 


5129 


46-00 


2770 


Marsh gas, CH 4 . . 


3840 


43'" 


36*45 


39'SO 


50*00 


Carbonic oxide, CO . 


573 


4*66 


4*45 


7"50 
3-80 


6-80 


Heavy hydrocarbons 


7-27 


475 


4-91 


I3-00 


Nitrogen, N . . . 


423 


4-65 


1 41 


0*50 


0*40 


Carbonic acid, CO a . 


0-37 


3*oa 


108 


— 


0*10 


Water vapour, H a O . 




— 


— 


200 


2 '00 



Analysis of London Coal Gas. 
(Hvmpidge.) 



1 


Sample (A) 


Sample (B) 


Hydrogen, H 

Marsh gas, CH 4 

Carbonic oxide, CO 

Olefines 

Nitrogen, N 

Carbonic acid, CO a 


vols. 
5005 
32*87 
12*89 

387 

032 


vols. 
5134 
35'28 
740 
356 
224 
038 



Analysis of Berlin and New York Coal Gas. 





Berlin 


New York Municipal 
Gas Light Co. 


Hydrogen, H 

Marsh gas, CH 4 

Carbonic oxide, CO . 

Ethylene, C2H4 .... 

Nitrogen, N 

Carbonic acid, COj 

Oxygen, O 


vols. 
4975 
3270 
o*54 
4'6i 
068 
2-50 

Q-22 


vols. 
30'30 
24-30 
26*50 
1500 
2-40 

l'OO 

050 



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Appendix I 



477 



Analysis of Natural Gas from Gas Wells in Pennsylvania. 
( Watts' ' Diet, of Chemistry: Supp. 3, Part 2.) 





Burns Butler 


Lechburgh 


Harvey 
Butler Co. 




Co.'s well 


Westmoreland Co. 




vols. 


vols. 


vols. 


Carbonic acid, CO* 


o*34 


o*35 


o'66 


Carbonic oxide, CO 


trace 


o'a6 


— 


Hydrogen, H 


6*io 


479 


I3"50 


Marsh gas, CH 4 . 


75 '44 


89-65 


8011 


Ethylene, C 2 H 4 . 
Hydrocarbons composition 


l8'I2 


4*39 


572 








not stated .... 


— 


056 


— 



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478 



The Gas Engine 



ll 

■ft 




3 

is 1 - 


fill 

1** 


•J 


2 2 2 




£ 




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■> ♦ m m ♦ ^ •♦ 



V»^> "ooo HD 00 VD *0» 00 <b 

f) ro fj ro f*"i en (*> f*i f*} ro 

JOMMtsto, + CO 

V*> V *r*> V V*> V "o *m *« *c*i 



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£*> 2*2. "2. 2«o no * iv moo ooqhm o c> o\ l 3 

_ . I 120 

3* 



m«(nM i«« « >0 



o n 



JO *•« w w p S ro « jS jS *yi « « S> -. S »J 

"h b b b b b b b b b b b b b b b b b b b 



o o '« •< o o o o h m *m b b b b b b b b b 



< j? a 



i c c >» 

"O «J U — 

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J <=£ 



w 5 «-2U 



rn o p p p p « m *o m m »n m« K a n^ 
inmiflinmin'in'inW "■♦ *m V Vr V V "m V V> Vj 



w « « « « ( 



i « m « n « « « « 



m o M ** ^ -*oo co n oommoOOO i^nm 
t «o ;e .tv y> ♦ « <p # ^ n t>. »o ^ oh QyJ 5. »o oo oo 
«o m f*> o*oo oo o oo vo t«> «o ^ in V» tn V+ *<«- Vo *«o *■♦ 









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V« WVnV»»Vn V VV<j 



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Appendix II 



479 




53. 3- en co co co^- co co 



CO CO ts ^ txOO CO t 

O •-< t» *<foo cooo c 
ioto* ^^ ,*., 



cow g\ co »o o to txoo 

cococ0cococococ0< 



« £S&cl8§-S\8>&8> R2<g£2 8,&$o&a 

S tO Ov O tx M O-th, NN Nh ^-J-QO MOO MOO 
f? Jo«0<0 iO iniOiO'O'O iototoiototo»ototo»o 



toco^coTt-ON^o tN\o 



tOOO »0 "*-0 m \T) CO ^ »0 



CO CO CO co CO CO 



CO CO CO CO 



00 q\ m co to ex o covo ►"• 00 o\w hoo co to m 
V rxo5 votxoJcoooco oodtxtx^r^woocoM 
> <*oo_ oo_ coco -* *t«> ^ "t*^ h l co ^ c ^9.^t' loe l 



q 

M H O O 



m « w ca m 1 






0>o * tx 



p\ o\ n w co' 



,N 8>o? 



cococococOcooo^c 



P 0& \p t?> tN tx 5 P JO ts. 

cocooocococococoM CO 



NO »rvQ -*-vO *■ M *f M 

co O cs65 rxvo d\ co c> h 
m tx Ox ovoo On*o ^t- w tx 



■^COCOCOCOCOCOCOCOCO COMMMMMMMCOM 



ts C>» M Q CO M COv© fs Q\ 
p\ ft OvO M m «* tx CO\5 

"o» »o "co to "on b> lovb <© 00 

nn«nc«Mct(4MN 

8t-i Cv 0\\Q H- « O m m 
On CO tx M COO m tNOO 
m vfi OWO COCi txtotOM 



»0\0 N 00 CO to N 00 C0»O 
tONOOO COCOCOCO CTvOO 

CO P> JH p. JO ^f ON tX 4 tN <*■ 

^CO^COCOCOCOCOCOfO 



COvC 'S tN »0 »00 to O 00 

COOO m M p m 00 00 toop 

COM CO CO CO CO N M COM 



"0 • . 

o' a . . P . 

3§.--tt---- 

li^iiiifiiiiiiliiil'y 



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48o 



The Gas Engine 



Table III. calculated from Table I. 

Oxygen or air required for complete combustion of i vol. of each of the 
following gases. 



Town 




Oxygen 


Air 


Vol. of products 




vols. 


vols. 




Edinburgh .... 


i*5S 


7-40 


825 


Glasgow . 






1*44 


6-85 

708 


7*S | 


St. Andrews 






149 


7*8 | 


Liverpool 






i'37 


6-52 


5*45 ' 


Preston . 






1-28 


610 


6*88 | 


Nottingham 






130 


6*17 


614 


Tweeds 






I '40 


667 


7*47 


Sheffield . 






1-36 


6*49 


7*28 


Birmingham 






109 


5"i9 


608 


Bristol . 






1-29 


616 


6*95 


London — 








Gaslight & Coke Co. . 


1*20 


5*7* 


6'53 


South Metropolitan Co. 


* 15 


5*47 


6*20 


Redhill 


I '22 


5*82 


658 
6-69 


Gloucester .... 


1*25 


5*94 


Newcastle-on-Tyne . 


"5 


549 


6*24 


Newcastle-under-Lyme . 


1 '20 


572 


648 


Brighton 


1 18 


562 


636 


Southampton .... 


1 17 


5|6 


6*29 


Ipswich 

Norwich 


i'i8 


5*63 


6*31 


1 18 


563 


6'39 



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LIST OF BRITISH GAS AND OIL ENGINE 
PATENTS 

FROM THE YEAR I79I TO 1 897 INCLUSIVE. 

When patents are communicated \ the names of the communicators are printed 
within parentheses, 

1791. 

1833. John Barber. — Using inflammable air for the purpose of producing 
motion. 

1794. 

1983. Robert Street. — Method of producing an inflammable vapour force by 
means of fire, flame, &c. 

1797. 

2164. James Glaze brook. — Working machinery by means of the properties 
of air. 

1801. 

2504. James Glazebrook. — Power from mixtures of air, such as hydrogen, 
nitrous air, &c. 

1817. 

4179. J. C. Niepce.— Propelling vessels by explosive gases. 

1823. 

4874. Samuel Brown.— Effecting a vacuum by flame, and thus producing 
power. 

1826. 

5350. Samuel Brown.— Improvements in his former patent, No. 4874. 
5402. £. Hazard. — Preparing mixtures of vapours with air, and exploding 
them to obtain motive power. 

6525. L. W. Wright. — Explosive engine. Carburetted hydrogen and air are 
forced into reservoir and exploded. 

I I 



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482 The Gas Engine 

1835- 

NO. 

6875. J. C. Douglass. —Explosion engine. 

1838. 

7615. W. Bar net t.— Obtaining motive power from inflammable gases by 

compression and explosion. 
7871. Byerley & Collins.— Using of steam or gas, or both combined, with 

the hydrostatic paradox. 

1839. 
8207. II. rinkus.— Motive power obtained either by explosion or exhaustion. 

1840. 
8644. Henry Pinkus.— Explosion engine. 

1841. 
8841. James Johnson. —Motive power obtained by the explosion of oxygen 
and hydrogen. 

1843. 
9972. Joseph Robinson. —Engine driven by inflammable gas or vapour. 

1844. 
10404. J. W. B. Reynolds.— Gas or pneumatic locomotive engines ; explosion 
of a mixture of gas and air. 

1846. 
1 1072. Samuel Brown. — Improvements in gas engines and in propelling car- 
riages and vessels (no specification enrolled). 
1 1245. W. Cormack.— Motive power is obtained by contraction and rare- 
faction. 

1850. 
13302. E. C. Shepard. — Explosion engine. 

1852. 
940. N. Seward. — Motive power. Gunpowder. 

979. W. Quaterman (provisional only). — Motive power by gaseous matter. 
14086. Samuel Hasel tine.— Improvements in engines to be worked by air or 

gases (no specification enrolled). 
1 41 50. A. V. Newton.— Gas engine. 

1853- 

362. Robert Roger (provisional only).— Obtaining motive power by ex- 
plosion. 
515. R. L. Bolton. — Motive power is obtained from the explosion of gases. 



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Appendix II 483 



NO. 



1248. E. J. Schollick. — Water is decomposed by electric currents into its 

component gases, which gases pass into a cylinder, and are exploded 

by another electric apparatus. 
1577. Joseph Webb (provisional only) Improvements in obtaining and 

applying motive powers (gas and electricity) by explosion. 

1648. Fabian Wrede Improvements in gas and air engines. 

1 67 1. A. Carosio (provisional only). —Producing explosive gases electro- 

magnetically. 

i8 54 . 

191. James Anderson (provisional only). — Motive power obtained by air, 

gases, or vapour. 
549. J. C. Edington (provisional only). — Mixture of carburetted hydrogen 

and air, exploded in a cylinder. 
1072. Barsanti & Matteucci (provisional only). —Apply the explosion of 

gases as a motive power (atmospheric engine). 

1855- 

3*9. T. B. Blanchard. — Motive power from combustion. 

562. . Alfred V. Newton. — Improvements in engines worked by explosive 

mixtures, 
ion. Henri Balestrino (provisional only). — Improvements in obtaining 
motive power by aid of explosive gases. 

i8 5 6. 

1807. C. J. B. Torassa. — Improvements in obtaining motive power by aid 
of explosive gases. 

1857- 

1655. Barsanti & Matteucci. — Improvements in obtaining motive power 

from explosive gases. 
1754. J. S. Rousselot — Improved method for obtaining motive power, and 

engine for applying the same. 
2408. J. E. F. Luedeke. — Motive-power engine (explosion). 

1858. 
969. W. Clark. — Burnt air motor. 

996. C. D. Archibald.— Treating air or gases for purposes of motive power. 
2648. R. Nelson. —Vacuum obtained by ignited hydrocarbon fluids. 

1859. 

784. T. M. Meekins.— Production of motive power, and projectile and ex- 
plosive force (provisional protection refused). 
1227. J. Nasmyth.— Improved apparatus for obtaining and applying motive 
power. 

112 



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484 The Gas Engine 



NO. 



1345. P, Gambardella. — Obtaining motive power from mixture of hydrogen 

and oxygen, exploded by electric spark. 
2767. J. Anderson. — Coal is partially burned and wholly distilled in a furnace 

into which the proper quantity of air is introduced. 

i860. 

335. J. H. Johnson. — Improvements in obtaining motive power. 
615. Pierre Hugon. — Gas and air exploded in bent tube over water. 
878. Michael Henry. —An explosive mixture ignited by the electric spark. 
1585. II. F. Cohade.— A mixture of air and gas is exploded in a chamber 

furnished with a valve to produce pressure. 
2743. W. E. Newton.— Heating apparatus consists of a burner from which 
hydrogen under pressure escapes and is ignited by an electric spark. 
2902. Pierre Hugon. — Improved method for igniting explosive gaseous com- 
pounds. 

1861. 

107. J. H. Johnson. — Improvements upon the reciprocating gas motive 
power engine, No. 335/1860. 

166. Jean B. Pascal. -Application of inflammable gas, produced by decom- 
position of steam, to explosion engine. 

3270. W. E. Newton Force generated by the explosion of a mixture of 

atmospheric air and hydrogen. 

1862. 

2143. C. W. Siemens (provisional only). — Mixed air and gas are admitted 
into the working cylinder and ignited by electricity. 

3108. Jacques Arbos.— A gas engine with apparatus for generating gas, 
forming one apparatus. 

1863. 

653. Pierre Hugon. — Explosive force of the gaseous mixture acts upon an 
intermediate column of water, and thus indirectly upon the piston. 

1449. W. Clark.— Effecting the combination of oxygen with the fuel, and 
their intermixture with the burning products of combustion, causing 
motive power. 

2098. R. A. Brooman. — Improvements in air and gas engines. 

1864. 

1099. M. P. W. Boulton — In connection with the mode of working steam 
and caloric engines to employ that portion of heat which is generated 
by combustion of the fuel. 

1 173. F. II. Wenham Engines worked by explosive mixtures* 



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Appendix II 485 



NO. 



1288. J. E. Holmes (provisional only) Vacuum by explosion. 

1291. M. P. W. Boulton. — Improvements in engines worked by heated air 
or gases mixed with steam. 

1599. B. F. Stevens. -Applying petroleum vapour mixed with air. 

1636. M. P. W. Boulton Improvements in obtaining motive power from 

aeriform fluids. 

3044. M. P. W. Boulton Improvements in healing aeriform fluids by in- 
jecting some substance in a state of fusion (chlorides, &c. ). 

i86 S . 

501. M. P. W. Boulton.— Improvements in obtaining motive power from 

aeriform fluids and from liquids. 
827. M. P. W. Boulton. — Obtaining motive power from aeriform fluids and 

liquids. 
905. John Pinchbeck (provisional only). —The connection of the exhaust 
pipe of the cylinder with a condensing chamber of engines worked 
by explosion of air and gas. 

986. Pierre Hugon Effecting the combustion or explosion of gases by 

means of slide valves carrying gas burners supplied with gas under 
pressure. 

191 5. M. P. W. Boulton Improvements in obtaining motive power when 

heated air or aeriform fluid is employed. 
1992. M. P. W. Boulton. — Method for utilising a larger portion of heat. 
2600. W. E. Gedge. — Expansion engine. 

1866. 

27. T. T. Macneil (provisional only). — Motive power is produced by means 

of a receptacle containing incandescent fuel into which is forced 

the requisite air for combustion. 
181. W. Clark (provisional only).— Motive power, heated gas or air. 
434. C. D. Abel. — The explosion of a mixture of air and gas drives up a 

light piston. 
434. C. D. AM. — Gas engine in which the explosion of air and gas, ignited 

by a gas jet or electric spark, drives up a piston. 

434. C. D. Abel Regulating power of explosion. 

738. M. P. W. Boulton. —Generating and applying heat for the production 

of motive power and steam. 
3125. R. George. — Improvements where motive power is obtained by action 

on a piston traversing to and fro within a vibrating cylinder. 
3363. J. Anderson.— Improvement on No. 2767/1859, the connection of 

the piston with shield shell. 
3448. W. Clark. — Improvements in manufacture of hydrogen gas and its 

applications for lighting and heating, and as a motive power. 



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436 The Gas Engine 

1867. 

NO. 

422. R. Shaw (provisional only). — Explosion engine details. 
499. Kinder & Kinsey. — Improvements in gas engines. 
571. A. V. Newton. — Improvements in gas engines. 

633. A. L. Normandy. — Improvements in engines worked by heated air or 
gases. 

1392. William Smyth. —Motive power for actuating apparatus for navigating 

the air. 

1575. H. A. Bonneville.— Obtaining motive power by means of an over- 
heated mixture of air and steam. 

2245. C. D. Abel. — Combined gas and air engine. The explosion of a mix- 
ture of gas and air propels a light piston. 

3237. W. E. Gedge (provisional only). — The burnt gases are condensed after 
their action upon the driving piston in order to produce a vacuum. 

369a W. E. Newton.— Motors for generating motive power. 

1868. 
354. A. M. Clark. — Manufacture of gases for a gas engine. 

1393. G. B. Babacci.— A vertical gas engine. 

1878. J. Bourne. — Production and application of motive power. Air and 
fuel, either solid, powdered, liquid, or gase us, are blown, after being 
made hot, into a hot chamber, a pump or steam jet being used. 

1988. M. P. W. Boulton. — Apparatus for obtaining motive power by the 
combustion of aeriform inflammable fluid. 

2264. J. Gill.— Improvements in the construction of engines for motive 
power. 

2680. J. M. Hunter. — A vessel is provided with motive power for aerial pro- 
pulsion— explosion of mixture. 

2808. Bower & Hollinshead. — The construction of engines in which the 
motive power is derived from-the force of the explosion of air and 
gas. 

3146. J. Robertson. —The generation of steam or gases to actuate motive 
power engines. 

3264. E. A. Rippingille.— Motive power obtained by mixing the products 
of combustion with steam. 

3594. John Bourne.— Production of heat, and generation and application of 
motive power. 

1869. 
1375. Franklin & Dubois (provisional only). — Gas engine. 
1435. II. Bessemer.— Blast furnaces and blast engines, and utilising the 

gaseous products from blast furnaces. 
1748. A. M. Clark (provisional only).— Apparatus for producing motive 

power by the use of steam or compressed gases. 



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Appendix IT 487 



WO. 



3087. Hydes & Bennett.— Propelling ships by means of heated compressed 
air and products of combustion combined. 

3178. A. H. Brandon.— Gas or vapour engine. 

3585. W. Hetherington.— Improvements in the arrangement and con- 
struction of motive power engines which are actuated by heated air 
or gases. 

3705. J. Bourne.— Production of heat and motive power, the combustion of 
solid, liquid, or gaseous fuel. 

1870. 

194. J. M. Plessner.— Treatment of hydrocarbons and air to produce motive 

power. 
440. A. H. de Villeneuve. — Machinery for generating, obtaining, and 

applying motive power. 
1352. £. P. H. Vaughan (provisional only). — Construction of gas engines in 

which a mixture of air and combustible gas is introduced into a 

cylinder between two pistons. 
^59. John Bourne.— Motive power is produced from heat derived from the 

combustion of solid, liquid, or gaseous fuel, and from coal reduced 

to powder. 
2554. William Firth (provisional only).— Improvements in steam, air, and 

gas engines. 
2959. E. P. H. Vaughan.— Gas engine, in which the mixture of air and 

combustible gas is introduced into the cylinder between two pistons. 

1871. 

1724. E. N. Schmitz. — An improved gas engine. 

2254. G. Haseltine.— Motive power produced by the explosive force of 
gas. 

2326. J. Anderson. — Froducing current and developing motive power mainly 
by igniting a mixture of combustible gas and air in a chamber or 
channel, near an orifice, through which the gases of greatly increased 
volume, due to the combustion, issue in the form of a jet. 

2587. J. M. Plessner. — Obtaining motive power from the explosion of gases. 

1872. 

387. W. R. Lake. — Engines operated by gunpowder, gun-cotton, or other 

explosive material. 
821. M. A. Soul. — Navigable balloon worked by a gas engine. 
1 1 26. T. N. Palmer (provisional only). — An explosive gas engine. Any 

fluid carburetted hydrogen gas or fluid, in the form of spray, is 

introduced into a cylinder, where by the access of atmospheric air 

its combustion produces motive power. 



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488 The Gas Engine 

NO. 

1423. P. Jensen.— The construction of coke ovens and utilisation of the 
waste heat therefrom for generating gas for gas engines and other 
purposes. 

1594. W. E. Newton. — Explosion engine. 

2293. J. Young. —Motive power obtained from vapours given off by the 
volatile hydrocarbons obtained from petroleum and paraffin oils. 

3228. W. R. Lake.— The warming of air (for heated air motor) effected by 
means of tar, or other cheap liquid fuel, placed in a closed cylinder 
and ignited. 

3481. E. T. Hughes (provisional only).— The use of any liquid hydrocarbon, 
such as naphtha or petroleum, which in a divided state, mixed with 
atmospheric air, is injected behind a piston in a cylinder, and when 
ignited, produces power by the explosion or combustion. 

3641. G. Haseltinc. — Utilising the vapour of hydrocarbon oils or the pro- 
ducts thereof, or similar substances, for obtaining motive power. 

1873- 

272. W. E. Sudlow.— Rotary engines worked by hot air, gas, explosive or 

otherwise, or by water pressure or steam. 
329. G. Rydill. — Steam boilers and furnaces, heating air and gases, and 
producing motive power from a mixture of steam and products 
of combustion for working a steam engine, and for other purposes. 

1628. J. Imray (provisional only). — Method of and apparatus for obtaining 
motive power from heated air, gas, or gaseous products of combus- 
tion admitted to a cylinder at the pressure of the atmosphere. 

1946. J. Imray.— Obtaining motive power from heated air, gas, or gaseous 
products of combustion admitted to a cylinder at the pressure of the 
atmosphere and cooled therein, so that their pressure on one side 
of the piston being reduced below that of the atmosphere, the ex- 
cess of atmospheric pressure on the other side of the piston shall 
effect its propulsion. 

3848. W. R. Lake. — Gas engines driven by the explosion of combustible 
gas or vapour mixed with air. 

4088. F. W. Turner. — Gas engines, in which a wheel, arranged with a pro- 
jecting rim having bevelled grooves on the inside, is keyed on the 
main shaft. 

1874. 

25. R. Gottheil. — An explosive gas engine, having a cylinder open at one 
end, and provided with two pistons, one of which may be termed 
the working piston, and is connected in the usual way to a crank on 
the main shaft, while the other, which may 1* called the loose piston, 
has a rod passing through the cylinder cover, and through the t*o 
friction cheeks mounted on levers, so as to admit of free movement 



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Appendix II \ 489 

NO. 

of the piston rod in one direction, while its movement in the other 
direction is checked, owing to the cheeks embracing the rod tightly. 

414. C. D. Abel. — Gas engine, in which a slide is arranged to operate upon 
a single passage for inlet to and outlet from the cylinder ; this 
engine is regulated by a governor, so as to economise the expendi- 
ture of gas. 

486. S. Ford. — A rotary gas engine worked by the explosive force of gas. 

493. J. Hock. — Engines worked by the combustion of petroleum, naphtha, 
or other liquid hydrocarbons, such combustion producing pressure 
in a cylinder to work a piston connected to a crank on a fly-wheel 
shaft. 

509. R. M. Marchant. — Combined air, steam and caloric engine. 

605. C. D. Abel. — Improvements in gas motor engines. 

777. J. D. Ridley. — Aerial machine, in which a piston actuates the wings of 
the apparatus, causing it to reciprocate in a cylinder by alternate 
explosions of gunpowder, or other explosive agent, fired by elec- 
tricity. 

961. C. Carobbi & G. Bellini. — Locomotive and other engines, worked 
by air compressed by the combustion of fulminating matters, such 
as cotton, hemp, linen, tow, or similar substances, formed into a 
rope, and treated with a mixture of concentrated azotic and sul- 
phuric acid. 
1652. E. Butterworth (provisional only).— Preventing the overheating of a 

cylinder, exhaust valve, and adjacent pipes. 
2209. G. Haseltine.— Improvements in gas engines. 
2441. F. Jenkin. — Thermo-dynamic engine, or * fuel engine,' the primitive 

type of which is Stirling's air engine. 
2 795- J- H. Johnson. — Generating and applying the motive power of gases. 

3189. R. M. Marchant (provisional only).— Combined air, steam, and caloric 

engines. Gas used as fuel. 

3190. R. M. Marchant (provisional only). — Steam and other motive power 

engines, and manufacture of gas. 
3205. F. W. Crossley. — Improvements in gas motor engines. 
3257. C. T. E. Lascelles. — Gas engines for propelling tramway cars and 

other vehicles. 
4410. Kirkwood, Lascelles, & Hall (provisional oily).— Gas engines used 

as motors for tramway cars and other vehicles. 

1875- 

71. CD. Abel. — Motor engines worked by gas or combustible vapour and 

air. 
175. P. Vera. — Gas and hot air engines. 
265. E. C. Mills and H. Haley. — Explosive gas engines. 
744. J. F. Dickson.— Improvements in air and gas engines. 



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490 The Gas Engine 



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2016. De V. Bruce & T. M. Antisell.— Utilising the expansive force of 

vapours or gases, either by gradual pressure or explosion, in 

engines. 
2334. W. W. Smyth & G. C. Hunt. —Gas engine with two single-acting 

cylinders. 
2826. R. Hallewell. — Explosive gas engines. 

3221. F. W. & W. J. Crossley.— Improvements in gas motor engine. 
3274. Q. L. Brin. — Obtaining motive power by the explosion of gas and air 

acting directly or indirectly on water or oil. 
3615. C. D. Abel. — Improvements in gas and air engines. 
4326. J. H. T. Ellerbeck&J. M. Syers. — Explosive gas motor (provisional 

only). 
4342. E. P. Alexander.- Gas motive power engines, and means of regulating 

and transmitting their motion for driving, sewing, electric, and other 

machines, and fans or pumps. 

1876. 
88. Thacker (provisional only).— Improvements in gas engines. 
132. Crossley.— Improvements in gas motor engines. 
1034. Kidd (provisional only). — Improvements in gas-producing furnaces 

and in the methods of utilising the gases generated therefrom. 
1520. Wirth (Humboldt Manufacturing Co.). — Improvements in gas engines. 
1961. Lascelies.— Improvements in gas and other explosive motive power 

engines. 
2081. Abel (Otto). — Improvements in gas motor engines. 
2288. Boulton. — Improvements in apparatus whereby combustion under 

pressure is applied to generate fluid for working engines. 
2824. Linford. — Improvements in gas engines and in appliances connected 

thereto. 
3 191. De Kierzkowski. - - Improvements in pressure generators for motive 

engines, and in the application of motive engines to the propulsion of 

tram cars, &c. 
. 3370. Redfern (Sack& Reunert). — Improvements in gas motor engines and 

in apparatus connected therewith. 
3435. Simon (provisional only). — Improvements in the construction of 

engines to be worked by power derived from air and oil com- 
bined. 
3444. Johnson (Wertheim). — Improvements in obtaining and applying 

motive power, and in the apparatus employed therein. 
3620. Boulton.— Improvements in engines worked by the combustion and 

expansive force of an inflammable fluid mixture. 
3767. Boulton. — Improvements in apparatus for the production of motive 

power jointly by the elastic force of products of combustion, and of 

steam or vapour. 



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4987. I Iallewell.— Improvements in gas motor engines. 

4988. I lallewell.— Improvements in gas and water motor engines. 

1877. 

252. Clerk.— Improvements in motive power engines working with hydro- 
carbon gas or vapour. 
491. Otto & Crossley. — Improvements in gas motor engines. 
711. Roberts (provisional only). — Improved machinery or apparatus for 

propelling tramway cars and other like vehicles. 
766. Boulton. — Improvements in engines worked by products of combustion 

either alone or in conjunction with other elastic fluid. 
819. Hallewell.— Improvements in gas motor engines and in the valve of 

such engines. 
1063. Lake (Wertheim).— Improvements in gas motor engines. 
1470. Linford. — Improvements connected with gas engines. 
2177. Crossley (F. VV. & W. J.). — Improvements in gas motor engines. 
2334. Robson. — Improvements in engines operated by the combustion of gas 

or vapour. 
2621. Simon & Millier (provisional only). — Improvements in gas engines. 
2749. Simon. — Improvements connected with atmospheric gas engines. 
3024. Mills & Haley. -Improvements in motive power engines worked by 
the explosion of gas. 

3121. Wilson and others (provisional only). — Improvements in engines, and 

apparatus for the propulsion of vehicles on roads and rails. 

3122. Wilson and others (provisional only). — Improvements in gas motors. 
3159. Johnson (La Societe' des Moteurs Lambrigot). — Improvements in 

effecting the conversion of hydrocarbons, &c, into gas, and in 

apparatus or means employed therein, and in or for the production 

and application of gaseous mixtures. 
4052. Weyhe. — Improvements in gas motor engines. 
4937. Simon (Kindermann) (provisional only). —Improvements in gas motor 

engines. 

1878. 

10. Hilton & J. & S. Johnson (provisional only). — Improvements in the ap- 
plication of gas motors to tram cars and other self-propelling vehicles. 
228. Ramsbottom. — Improvements in engines for obtaining motive power 

from liquid and gaseous fluids, and for pumping and compressing. 
29a Pieper (SchaefTer) (provisional only). —An improved gas motor. 
433. Simon (L. & R.). — Improvements in and connected with gas engines. 
942. Linford.— Improvements in gas engines. 
1 170. Baron. — Improvements in motive power engines. 
1770. Abel (Otto) (provisional only). — Improvements in apparatus for 
igniting the charges of gas motor engines. 



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492 The Gas Engine 



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1798. Halle well.— Improvements in gas engines, applicable in part to 
other uses. 

1997. Ilannoversche Maschinenbau-Actien-Gesellschaft, The. — Improve- 
ments in gas engines with two pistons. 

2037. Clayton. — Improvements in gas motor engines and in apparatus con- 
nected therewith. 

2278. Boulton (provisional only) Improvements in gas motor engines. 

2474. Johnson (Francois). — Improvements in obtaining. motive power and 
in the machinery or apparatus employed therein. 

2525. Boulton (provisional only). — Improvements in gas motor engines. 

2609. Boulton (provisional only). — Improvements in gas motor engines. 

2707. Boulton. — Improvements in combined gas and steam motor engines. 

2901. Waller. — Improvements in gas, steam, air, and other motive power 
engines and in apparatus in connection therewith. 

3045. Clerk. — Improvements in gas motor engines. 

3056. Leichsenring. — Improvements in and relating to engines worked by gas 
or other fluid, partly applicable to apparatus for compressing fluids. 

3444. Cropper & Johnson. — Improvements in valves for gas engines. 

3774. Casson (provisional only). — Improved means and apparatus for work- 
ing clocks and bells (by combustion of gas). 

3972. Weatherhogg. — Improvements in gas motor engines. 

4630. Foul is (provisional only). —Improvements in motive power engines. 

4760. Duncan & W. G. Wilson (provisional only). — Improvements in gas 
motors. 

4782. Lake (Lay) (provisional only). — Improvements in apparatus for pro- 
pelling, guiding, &c, torpedo boats. 

4843. Foulis. — Improvements in gas and hydrocarbon engines, and in ignit- 
ing the gas or hydrocarbon, applicable for other purposes. 

4979* Simon and another. — Improvements in and connected with gas or 
hydrocarbon engines. 

4987. Lake (Lay).— Improvements in apparatus for propelling, guiding &c 
torpedo boats. 

5092. Hallewell. — Improvements in gas motoT engines. 

51 13. Crossley and another.— Improvements in gas motor engines. 



1879. 

2. Williams & Baron. — Improvements in and relating to atmospheric 
air and gas motor engines. 
309. Pieper (Krauss).— A gas power locomotive for tramways and for rail- 
ways of secondary order. 
392. Shaw (provisional only).— Improvements in gas motor engines. 
495. Boulton.— Improvements in caloric engines. 



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Appendix II 493 



NO. 



540. Donald (provisional only). —Improvements in and connected with gas 

engines. 
75a Simon (Todt) (provisional only). —Improvements in vapour or gas 

motor engines. 
1 161. Grad don. —Improvements in machinery or apparatus for generating 

motive power &c. &c. 
1270. Turner.— Improvements in and relating to gas motor engines. 
1450. Hallewell.— • Improvements in compound gas engines. 
1 500. Linford. — Improvements in gas engines. 
1727, Purssell (provisional only).— Improvements in gas engines to adapt 

them for locomotive purposes. 
1912. Holt & Crossley (provisional only). — Improvements in machinery for 

starting, propelling, and stopping vehicles, and in the apparatus and 

appliances connected therewith, more particularly with reference to 

gas engines &c. &c. 
I 933* Sombart (Buss). — Improvements in gas engines. 
1947. Newton & Cowper (provisional only). — Improvements in prime 

movers and apparatus actuated by fluid pressure, applicable wholly 

or in part to pumps and other apparatus. 
1996. Clark (Fell). — Improvements in the production of motive power and 

in apparatus for the same. 
2073. Foulis. — Improvements in that class of motive power engines known 

as gas or hydrocarbon engines. 
2152. Woolfe. — Improvements in the construction of gas motor engines. 
2 191. Benson (Rider). — Improvements in gas engines. 
2193. Hurd.— A condensing or non-condensing compound single or double 

acting motive power engine, worked by explosive gases, collected 

from mines or otherwise, in combination with or without gun-cotton, 

or with gun-cotton alone, &c. 
2424. Clerk. — Improvements in gas motor engines. 
2618. Butcher (provisional only). — Improvements in gas motor engines. 
2732. Johnson (provisional only). — Improvements in gas engines. 
3140. Clayton. — Improvements in motor engines worked by gas or com- 
bustible vapour and air. 
3213. Atkinson. — Improvements in gas and similar engines and mechanism 

connected therewith, partly applicable to other purposes. 
3233. . Simon. — Improvements in gas engines worked by the combustion or 

explosion of a compressed mixture of gas and air or hydrocarbon 

and air. 
324$. Abel (Daimler). — Improvements in gas motor engines. 
3467. Dalton & Ken worthy. — Improvements in propelling carriages and in 

the apparatus employed therein. 
3561. Picking & Hopkins. — Improvements in gas motor engines. 
3732. Glaser ( Wittig& Hees). — Improvements in gas and petroleum engines. 



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494 The Gas Engine 

NO. 

3905. Alexander (Angele) (provisional only).— Improvements in gas motors. 

4 1 01. Emmet & Cousins. — Improvements in gas engines. 

4337. King. — Improvements in and connected with engines actuated by the 

explosion or combustion of a mixture of gas and air. 
434a Williams. — Improvements in and relating to atmospheric air and gas 

motor engines. 
4377. Butcher. — Improvements in gas motor engines. 
4396. Purssell. — An improved arrangement of apparatus for moving tram 

cars &c. by gas engine power. 
44S3. Graddon (provisional only). — An improved motive power engine 

actuated by an explosive fluid or gas, part of which may be applied 

to other gas engines. 
4485. Wigham (provisional only). — Improvements in gas motor engines. 
4492. Shaw (provisional only). — Improvements in gas motor engines. 
4499. Holt & Crossley. — Improvements in machinery &c. for stopping &c. 

the direction of motion of vehicles on rails, &c. , more particularly 

applicable to gas engines, but also suitable for other motor engines. 
4501. Robson. — Improvements in gas engines. 
4755. Foul"'s. — Improvements in gas engines. 
4820. Edmonds (Francois). — A new or improved gas motor or engine and 

new arrangements of mechanism employed with the same. 
5052. Mills & Haley. — Improvements in gas motor engines. 

1880. 

9. Pottle. — Improvements in governors for steam engines and other 
motors. 

117. Robinson. — Improvements in gas motor engines. 

330. Linford. — Improvements in and connected with gas engines. 

343. Abel (Daimler). — Improvements in gas motor engines. 

473. Newton. — Improvements in crossheads for motive power engines. 

474. Butcher. — Improvements in tramway, locomotive, and other engines, 

and in apparatus connected therewith. 
533. Thompson (Geisenbcrger).— Improvements in and appertaining to 

gas engines, or engines actuated by the explosion or combustion of 

mixed gas or vapour and air. 
760. Edwards. — Improvements in motive power engines actuated by the 

combustion of a mixture of gas and air, or by the pressure of steam 

or other elastic fluid, parts of which invention are also applicable 

to other purposes. 
1 1 31. Johnson (provisional only). — Improvements in gas engines. 
1653. Beechey (provisional only). — Improvements in engines worked by 

gas and air or other hydrocarbons. 
1692. Williams & Malam. — Improvements in and relating to atmospheric 

air and gas motor engines. 



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Appendix II 495 



so. 



1736. Sombart (provisional only). — Improvements in gas engines. 
1969. Haigh & Nuttall. — Improvements in gas engines. 

2 181. Wordsworth (provisional only). —Improvements in gas motor engines. 

2182. Lake (Lay). — Improvements in apparatus for facilitating the control 

and operation of torpedo boats. 
229a Hardaker. — Improvements in road vehicles or velocipedes. 
2299. Livesey (Livesey). — Improvements in gas motor engines. 
2344. Robinson.— Improvements in gas motor engines. 
2422. Foulis. —Improvements in gas engines. 
3140. Lake (Breittmayer). — Improvements in gas engines. 
3176. Northcott. —Improvements in engines and apparatus for producing 

motive power (relating to gaseous fuel engines). 
3182. Turner. — Improvement in gas motor engines. 
341 1. Holt & Crossley. — Improvement in locomotives for tramways and 

light railways. 
3512. Aylesbury. — Improvements in gas engines or motors. 
3607. Jenner. — Improvements in gas engines. 
3652. Wilson. — Improvements in vertical steam and other motive power 

engines. 
3685. Williams & Malam. — Improvements in and relating to atmospheric 

air and gas motor engines. 
3869. Purssell. — Improvements in the construction, arrangement, and 

method of action of gas engines. 
3913. Lawson (provisional only). — Improvements in velocipedes and in the 

application of motive power thereto, applicable to other, &c. 
4050. Robson. — Improvements in obtaining and applying motive power. 
4075. Clayton. — Improvements in motor engines worked by gas or combus- 
tible vapour and air. 
41 59. Kesseler (Henniges) (provisional only). — Improvements in the Simon's 

steam gas motor with burning flame in the cylinder. 
4201. Jensen (provisional only). — Improvements in burners for producing 

and burning petroleum gas. 
4260. Robinson. — Improvements in gas motor engines. 
4270. Beechey. — Improvements in gas motor engines. 
4297. Crossley. — Improvements in gas motor engines. 
439S. Rhodes and others. — Improvements in gas motor engines. 
4419. Benson (Rider). — Improvements in gas engines. 
4547. MacFarlane (provisional only). — A new or improved gas engine. 
4633. Bickerton (provisional only). — Improvements in gas motor engines. 
4819. Muller. — Improvements in or additions to gas engines. 
4881. Simon & Wertenbruch. — Improvements in gas motor engines. 
5024. Home (provisional only). — Improvements in gas engines. 
5090. Foulis (provisional only). — Improvements in gas engines. 
5101. Richardson (provisional only).— Improvements in gas engines and in 

apparatus connected therewith for the supply of gas to them. 



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496 The Gas Engine 

NO. 

5130. Livesey (Livesey). — Improvements in compound gas motor engines. 

5219. Fiddes. — Improvements in gas motor engines. 

5269. Wigham (provisional only). —Improvements in locomotive engines for 

tramways, &c. 
5347. Robinson.— Improvements in engines to be worked by steam, air, or 

gas. 
5471. Hutchinson. — Improvements in gas motor engines. 
5479. Graddon. — Improvements in machinery or apparatus for obtaining and 

applying motive power, partly applicable to other purposes. 

1881. 
60. Abel (Otto). — Improvements in gas motor engines. 
125. Haddan (Nix & Helbig) (provisional only). —Improvements in gas 

engines. 
180. Foulis. — Improvements in gas engines. 
320. Sombart. — Improvements in gas engines. 
370. Holt & Crossley.— Improvements in connection with gas motor 

engines, and locomotives worked thereby. 
532. Fielding. — Improvements in gas motor engines. 
565. Allcock. — Improvements in gas engines. 

798. Ord (provisional only). — Improvements in gas engines. 

799. Graddon (provisional only). — An improved construction of gas engines. 
81 1. Haigh & Nuttall. — Improvements in the construction of gas engines. 
867. Wenham. — Improvements in combined gas and heated air engines. 

1074. Bauer & Lamart.— Improvements in gas engines. 

1089. Clerk. — Improvements in motors worked by combustible gas qt 
vapour. 

1 202. Boulton (provisional only). — Improvements in caloric engines wherein 
the working fluid is heated by internal combustion of gas. 

1363. Bickerton. — Improvements in gas motor engines. 

1382. Groth (Schoufeldt and another) (provisional only). — A new or im- 
proved reversible rotary engine. 

1388. Ewins & Newman- — Certain improvements in gas engines. 

1389. Boulton. — Improvements in caloric engines wherein the working fluid 

is heated by internal combustion of gas. 

1409. G wynne & Ellis. —Improvements in gas motor engines. 

1 541. Benier (provisional only). — Improvements in gas engines. 

1 723. Watson. — An improved method of exploding gases used in gas engines. 

17.63. Watson (provisional only). — Improvements in gas engines. 

1765. Edwards. — Improvements in motive power engines actuated by the 
combustion of a mixture of gas and air. 

2083. Robson. — Improvements in motive power engines. 

2122. Dougill. — Improvements in gas motor engines, in the method of regu- 
lating the speed thereof, and of admitting combustible material into 
the cylinder and allowing the escape of exhausted products, &c 



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Appendix II AffI 



NO. 



C227. Crossley.— Improvements in the method and apparatus for supplying 
gas to movable gas motor engines. 

2280. Ford. — Improvements in gas engines. 

2504. Siemens. — Improvements in gas motors and producers. 

2564. Wigham. — Improvements in locomotive engines for tramways, rail* 
ways, &c. 

2645. Pinkney. — Improvements in gas engines. 

2670. Mills. — Improvements in obtaining motive power. 

2765. Levassor. — An improved motive power engine. 

2919. Watson.— An improved means or method of exploding gases in gas 
engines. 

2931. De Pass (Kortung). — Improvements in gas engines. 

2961. Beechey. — Improvements in gas motor engines. 

2967. Wastfield (provisional only). — Improvements in gas engines. 

2990. Linford & Linford.— Improvements in and connected with gas engines. 

31 13. Eteve & Lallement. — A new or improved motive power engine 
operated by hydrocarburetted air. 

3275. Ord. — Improvements in gas motor engines. 

3330. Brydges (Schiltz). — Improvements in gas, hydrocarbon, and other 
motive power engines. 

3367. Boulton. — Improvements in engines wherein a piston is propelled in a 
cylinder by ignition of inflammable gas or fluid. 

3415. Justice (Osam). — Improvements in the utilisation of the gaseous pro- 
ducts of combustion, and in apparatus therefor (provisional only). 

3450. Crossley & Holt (provisional only). — An improved governor for gas 
motor engines. 

3527. Lucas. — Improvements in gas engines. 

3536. Stern, Clerk, & Handyside. — Improvements in refrigerating machines, 
and in part applicable to gas motors, &c. 

3561. Kirkhove & Snyers. — A new or improved method and machinery for 
direct propulsion of land, water, and aerial motors or engines, appli- 
cable also to stationary engines. 

3715. Williams. —Improvements in gas engines and the automatic generation 
of gas therefor. 

3786. Butcher. — Improvements in gas motor engines, and in arrangements 
for starting and re-starting the same. 

4086. Atkinson.— Improvements in gas engines. 

4137. Watson. — Improvements in obtaining motive power by means of com- 
bustible gas or vapour, and in apparatus therefor. 

4223. King.— Improvements in gas motor engines. 

4244. Abel (Spiel).— Improvement in motor engines worked by combustible 
gases or vapours and steam. 

42S8. Simon & Wertenbruch. — Improvements in the construction and 
method of action in gas engines. 

4340. Wordsworth and others. — Improvements in gas motor engines. 

K K 



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498 TJie Gas Engine 



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4402. Weatherhogg. — Improvements in single and double acting compound 

air and gas motor engines. 
4407. Drake & Muirhead (provisional only). — Improvements in and con- 
nected with gas engines. 
4493. Royle. — Improvements in and apparatus for lubricating steam and 

gas engines, and for other lubricating purposes, &c. 
4589. Benier & Lamart (provisional only). — Improvements in gas engines. 
4608. Watson. — Improvements in gas engines. 
4830. Lake (Lay). —Improvements in and relating to boats to be propelled 

by gas, &c. 
5178. Shaw. — Improvements in gas motor engines. 
5201. Tonkin. — Improvements in motive power engines actuated by the 

combustion or explosion of mixtures of gas or combustible vapour 

with air, &c. ; applicable to other purposes. 
5259. Rhodes (provisional only). — Improvements in and appertaining to gas 

engines or engines actuated by the explosion or combustion of mixed 

gas or vapour and air. 
5350. Siemens.— Improvements in engines worked by the combustion of 

gaseous fuel. 
5456. Williams.— Improvements in and relating to atmospheric air and gas 

motor engines. 
5469. Crossley & Holt. — Improvements in gas motor engines, part of which 

improvements are applicable to steam engines, &c. 
5483. Griffin. — Improvements in gas motor engines. 
5534. Beck ( Montelar). — A gas locomotor for the locomotion of carriages, &c. 

(provisional only). 
5575- Quick and another.— Improvements in tramway locomotives and other 

locomotives or motive power engines. 

1882. 

362. Turner. —Improvements in gas engines. 

397. Emmet. — Improvements in gas engines. 

417. Withers.— Improvements in gas engines. 

579. Johnson (Bis;chop). — Improvements in gas engines. 

614. Haigh & Nuttall.— Improvements in the construction of gas engines. 

659. Wastfield (provisional only). — Improvements in gas engines. 

678. Watson (provisional only). — Improvements in gas engines. 

703. Wordsworth & Lindley. — Improvements in gas engines. 

994. Fielding.— Improvements in and connected with gas motor engines. 

1026. • Niel. — Improvements in gas engines. 

1318. Beechey. — Improvements in gas motor engines. 

1330. Sumner. —Improvements in gas motor engines. 

1590. Skene. — Improvements in gas motor engines. 

1 7 1 7. Drake & Muirhead. — Improvements in and connected with gas engines. 



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Appendix II 499 



NO. 



1754. Anderson & Crossley. — Improvements in the ignition apparatus of gas 

motor engines. 
1868. Dufrene, Benier, & Lamart. — Improvements in gas engines. 
1874. Brown. — Improved means of, and apparatus for, the production of gas 

by the combustion of carbon compounds, &c. 
1910. Skinner (provisional only) — Improvements in engines which are driven 

by means of the explosive force of gases. 
2008. Glaser (Teichmann) (provisional only).— Improvements in caloric and 

gas power engines. 

2057. Sombart. — Improvements in gas engines. 

2058. Porteous. — Improvements in gas engines. 
2126. Worssam. — Improvements in gas motor engines. 

2202. Clayton. — Improvements in motor engines worked by gas or combus- 
tible vapour and air. 

2231. Russ (provisional only). — Improvements in the manufacture of gas for 
lighting, heating, &c, and for utilising the same for motive power. 

2257. Nobbs.— Improvements in gas engines. 

2329. Hutchinson. — Improvements in gas engines. 

2337. Guthrie (provisional only). — Improvements in and relating to engines 
and apparatus connected therewith for developing the expansive force 
of air or gas and utilising the same for motive power. 

2342. Watson (provisional only). — Improvements in gas engines. 

2345. Bickerton and another.— Improvements in and applicable togas motor 
engines. 

2423. Thompson (Marcus). — Improvements in or appertaining to motors 
actuated by the explosion of comminuted liquids, &c. 

2527. Davey. — Improvements in apparatus for the production of inflammable 
gas and applying its combustion for the production of motive power, 

2751. Braham & Seaion (provisional only). — Improvements in gas engines. 

2753. Wordsworth & Wolstenholme. — Improvements in gas motor engines. 

3375. Robinson. — Improvements in and apparatus for obtaining motive power 
for propelling vessels, pumping fluids, and other analogous purposes. 

3435. Abel (Beissel). — Improvements in gas motor engines. 

3449. Holt & Crossley (provisional only). — Improvements in gas motor 
engines. 

3540. Hargreaves. — Improvements in thcrmo-dynamic engines. 

3787. Davey. — Improvements in apparatus for generating elastic fluid under 
pressure ; available for working engines. 

3819. McGillivray. — Improvements in gas engines. 

4363. Clark (Schweizer). — Improvements in gas engines. 

4378. Atkinson. — Improvements in gas engines. 

4388. Atkinson. — Improvements in gas engines. 

4418. Watts & Smith. — Improvements in and connected with motors worked 
by combustible gas, vapour, steam, &c. 

4489. Crossley.— Improvements in gas motor engines. 

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5oo The Gas Engine 



NO. 



4755. Wastfield.— Improvements in and relating to gas engines. 

4773. Wastfield (provisional only). — Improvements in and relating to gas 
engines. 

4886. Baldwin (provisional only).— Improvements in gas engines and in 
apparatus connected therewith. 

4948. Clerk. — Improvements in motive power engines worked by combus- 
tible gas or vapour. 

5042. Oedge (Marti & Quaglio).— Improvements in rotary gas engines, 

5188. Ash bury and others.— Improvements in gas motor engines. 

5371. Russ (provisional only).— Improved arrangement of machinery for the 
manufacture of gas for lighting, heating, and motive power purposes. 

5506. Mewburn (Goubet). — An improved rotary gas or explosion engine. 

5510. Maynes. — Improvements in gas motor engines. 

5527. Dyson (provisional only). — Improvements in or applicable to gas 
engines employed in connection with tramcars, &c. 

5782. Watson.— Improvements in gas engines. 

5819. Whittaker. — Improvements in or applicable to gas motor engines. 

5825. Odling (provisional only). — Improvements in gas motor engines. 

5865. Butcher (provisional only).— Improvement in gas motor engines. 

6130. Clark (Laureni).— Improvements in gas engines. 

6136. Bcnnet & Walker. — Improvements in motive power engines, which 
improvements are also applicable to gas engines. 

6214. Watson. — Improvements in gas engines. 

1883. 

19. Forest. —An improved construction of gas motor engine. 
21. Wood head. — Improvements in gas motor engines. 
130. Oclling. — Improvements in gas motor engines. 
132. Lake (Maxim) (provisional only). —Improvements in gas engines. 
300. Williams. —An improvement in engines for motive power, compression, 

and other like purposes. 
326. Linford & Cooke. — Improvements in gas engines. 
388. Howard & Bousfield (provisional only).— Improvements in gas 

engines. 
499. Weatherhogg. — Improvements in air and gas motors and apparatus for 

the production of gas therefor. 
638. King & Cliff. —Improvements in gas motor engines. 
781. Townsend & Davies.— Improvements in gas motor engines. 
836. Imray (Schweizer) — An improvement in gas motor engines. 
911. Capell. — Improvements in motors worked by air, gas, &c. , or explosive 

mixtures, &c. 
999. Clark (Kabath) — Improvements in gas and other engines. 
1010. Andrew. — Improvements in gas engines. 
1019. Handford (Edison). — Improvements relating to the operation „ of 

electrical generators by gas engines. 



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Appendix II 501 



NO. 



106a Martini.— A new gas motor. 

1098. Wastfield. — Improvements in and applicable to gas engines. 

1 1 16. Steel & Whitehead. — Improvements in gas engines. 

1 501. Marchant & Wrigley. — Improvements in the application and storage 

of illuminating or other like gas to motors for driving tramcars or 

other vehicles, and for the purpose of starting and working gas 

engines, and in means employed. 
1677. Abel (Otto). — Improvements in gas motor engines. 
1722. Crossley (provisional only).— An improvement in gas motor engine 

slide apparatus. 
1835. Butcher. —Improvements in gas motor engines and in applying them 

to pumping purposes. 
2192. Justice (Hale). —Improvements in and connected with gas engine, 

and in the method and means for regulating explosive charge. 
2492. Picking & Hopkins. — Improvements in gas motor engines. 
2517. Haigh & Nuttall.— Improvements in gas engines. 
2561. Nash. — Improvements in the means for operating gas engines. 
2702. Pieper (Korting & Lieckfekl). --Improvements in gas motors. 
2706. Crowe and others. — Improvements in gas caloric motive engines. 

2790. Thompson (Marcus) Improvements in gas motor engines. 

2^27. Whitehead. —A new or improved gas motor engine. 
3041. Russom (provisional only). — Improvements in gas engines. 
3066. Andrew Improvements in gas motor engines. 

3069. Williams. —Improved means of, and apparatus for, converting recipro- 

catory into rotary motion in gas and other explosive engines, and in 
hydraulic, steam, air, or other fluid motors ; also for effecting and 
governing explosions in gas and other such engines, parts of which 
are also applicable as air and other fluid compressors. 

3070. Fielding. —Improvements in gas motor engines, in part applicable lo 

other engines. 
3079. Crossley. —Improvements in gas motor engines. 
3097. Dougill. — Improvements in gas motor engines. 
3135. Niel Improvements in the construction and arrangement of gas 

engines. 
3272. Kirchenpauer & Philippi. — Improvements in gas motor engines. 
3280. Foulis. — Improvements in gas engines. 
3336. Holder. —Improvements in gas motors. 

3383. I-ake (Cardie). — Improvements in and relating to gas engines. 
3568. Wordsworth & Lindley. —Improvements in gas motor engines. 
3703. Pickering.— Improvements in gas engines. 
4008. Dutton (Spiel). —Improvements in gas or inflammable liquid engines 

or prime movers. 
4023. Quack (provisional only).— Improvements in gas engines. 
4046. Clerk. — Improvements in gas motors. 



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$02 TJu Gas Engine 

NO. 

40S0. Griffin. — Improvements in the arrangement and construction of gas 

motor engines. 
4193. Racholz (provisional only) Improvements in oil-gas engines, whereby 

the said engine produces its own gas from oil waste. 
4242. Ladd (Serrell). — Improvements in and relating to gas engines. 
4260. Clark (Economic Motor Company). — Improvements in gas engines. 
4291. Andrew. — Improvements in gas engines. 

4455. lladdan (Schiltz).— Improvements in gas and petroleum engines. 
4816. Williamson and others. —Improvements in gas motor engines. 
5020. Briscall and another (provisional only). —Improvements in and relating 

to gas motor engines. 
5042. Lake (K.abath). —Improvements in electrical igniting apparatus for gas 

engines. 
5085. Bullock.— Improvements in gas motor engines. 
51 13. Bull — Improvements in gas engines. 
5265. Justice (Hale). —Improvements in and connected with gas engines, 

and in the means and method of supplying explosive charges thereto. 
5297. Wirth (Sohnlein) (provisional only). — Improvements in petroleum 

motors. 
5315. Johnson (Lenoir).— Improvements in gas engines. 

5331. Robson (provisional only) Improvements in gas engines. 

5406. Picking & Hopkins Improvements in gas motor engines. 

5543. Nash — Improvements in the construction of gas engires, and in certain 

methods of operating the same. 
5570. Williamson and others (provisional only). — Improvements in gas motor 

engines. 

5632. Nash. — Improvements in the construction of gas engines. 

5633. Nash. — Improvements in the construction of gas engines. 
5721. Mills. - Improvements in gas motor engines. 

5784. Groth (Daimler).— Improvements in gas or oil motors. 

5923. Sombart. — Improvements in gas engines. 

5928. Welch & Rapier.— Improvements in gas engines. 

5951. Campbell (provisional only). — Improvements in gas motor engine. 

5956. Wastfield. — Improvements in and relating to gas engines. 

5976. Tonkin. — Improvements in motive power engines actuated by the 
combustion or explosion of mixtures of gas or combustible vapours 
with air, parts of which improvements are applicable to other engines. 

1884. 

32$ Hargreaves. — Increasing efficiency of thermodynamic engines. 

454. Skene. —Improvements in gas engines. 

560. Steel <fe Whitehead.— Improvements in gas engines. 

1373. Sterne.— Exhaust silencer. 



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Appendix II 503 



NO. 



I457. Wtrth (Bernstein).— Improvements in apparatus for, and the method 

of, producing motive power by the explosion of coal or carbon dust 

and air. 
2088. Rodgerson — Improvements in gas motor engines. 
2135. Henderson (Eteve & Braam). — An improved petroleum or hydro- 

carbon engine. 
2289. Rockhill.— Improvements in or relating to brakes for gas or other 

engines. 
2715. Woodhead. — Improvements in gas motor engines. 
2854. Clayton. — Improvements in gas motor engines. 
2933. Fielding. — Improvements in gas motor engines. 
3039. Atkinson. — Improvements in gas engines. 
3495. Cobham & Gillespie. — Improvements in gas engines. 
3537. Holt & Crossley. —An improved apparatus for starting gas motor engines. 
3758. Griffin. — Improvements in piston-rod stuffing boxes for gas motor 

engines. 
3893. Holt. —Compressing pumps for gas motor engines. 

3986. Johnson (Deboutteville & Malandin) Improvements in gas engines. 

4391. Williamson & others. — Improvements in gas motor engines. 

4591. Munden Improvements in gas motor engines. 

4639. Pollock. - Improvements in valves for gas engines. 
4736. Wirth (Sohnlein). — Improvements in gas engines. 

4776. Spence. — Improvements in gas engines. 

4777. Crossley.— Gas motor engines. 

4880. Weatherhogg. — Improvements in gas motor engines. 

5007. Hill & Hill. — Improvements in engines worked by gas or vapour. 

5302. Johns & Johns.— Improvements in rotary gas engines. 

5303. Johns & Johns. — Improvements in rotary gas engines and other rotary 

motors. 
5412. Dewhurst. — Improvements in and connected with gas engines. 
5435. Park.— Improvements in rotary engines and pumps. 
5641. Butcher. -Improved igniting valve for gas engines. 
5797. Linford & Piercy.— Improvements in gas engines. 
6597. Shann. — Improvements in the machinery for obtaining rotary motion 

by the action of two forces on different cranks. 
6652. Johnson.— Improvements in apparatus for carburetting air. 

6662. Wiegand Improvements in gas engines. 

6784. McNeill Improvements in tramway locomotives driven by gas. 

7284. King Improvements in gas motor engines. 

7288. King. — Improvements in gas motor engines. 

821 1. Holt. — Compound gas motor engine. 

8232. Sombart. —Improvements in gas engines. 

8489. Green Improvements in gas motor engines, and in the means or 

method of supplying them with gas. 



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504 The Gas Engine 



NO. 



8565. Rogers. — Improvements in gas engines. 

8579. Shaw. — Improvements in gas motor engines. 

8637. Crossley. — Improvements in Otto and other gas engines. 

8960. Ainsworth. — Improvements in gas engine cylinders. 

9001. Guthrie Improvements in gas engines. 

91 12. (iroth (Daimler). — Improvements in gas or oil motors. 

9167.* Williamson and others. — Improvements in or relating to valves for gas 

motor engines. 
9544. Magee. — Improvements in gas engines. 
9645. Welch & Rapier. — Improvements in gas engines. 
9949. Capitaine (Benz & Co.). — Improvements in gas motors. 
10062. Norrington. — Improvements in means for assisting velocipedes and gas 

engines to start. 
10364. Wallace — Improved apparatus for converting reciprocating recti- 
linear motion into rotary motion. 
10483. Guthrie. — Improvements in caloric engines. 
1 1086. Butterworth. —Improvements in motors worked by combustible gas 

or vapour. 
11 361. Justice (Backeljau). — Improvements in and connected with automatic 
gas motors. 

1 1 576. Griffin Improvements in apparatus for lubricating gas and other 

motor engines and machines. 
1 1 578. Crossley. —Improvements in gas motor engines. 
1 1 7 50. Douglas. — Improvements in gas engines. 
1 1837. Clark (Hopkins) — Improvements in gas engines. 
12201. Griffith. — Improvements in and connected with gas engines. 
12254. Davy. — Improvements in gas engines. 
1 23 1 2. Brine — Improvements in gas engines. 
1 23 1 8. Dciugill. — Improvements in gas motor engines. 
1 243 1. Purnell. — An improvement in gas motor engines: 
12603. Hill & Hill. — Improvements in engines worked by gas or 

vapour. 
12640. Tellier.— Motive power by gas, steam, combustible fluids, &c 
127 14. Reddie (Murray). — Improvements in gas engines. 
12776. Wilson — Improvements in the construction of tramway engines 

driven by gas. 
1 322 1. Andrew. — Improvements in gas motor engines. 
13283. Redfern (McDonough) — Improvements in gas engines. 
x 3573- Fairf ix.— Improvements in rotary and reciprocating engines. 
13776. Parker.— Improvements in gas motor engines. 
13935. Lawson.— Improvements in gas engines for pumping water and for 

other uses. 
143 1 1. Griffin — Improvements in gas motor engines. 
1434 1. Browett. —Improvements in gas motor engines. 



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Appendix II 505 



NO. 



145 1 2. Prentice & Prentice Apparatus for igniting gas engine charges at 

starting. 

J4765. McGillivray Improvements in gas engines. 

15248. Johnson (Deboutteville & Malandin). — Improvements in carburetters. 

1 531 1. Holt & Crossley Compound gas motor engine. 

1 53 1 2. Holt Gas motor engine. 

15633. Newton. — Improvements in gas motor engines. 

16131. Benier Improvements in hot air engines. 

16404. Atkinson. — Improvements in gas engines. 

16634. Muller and others Improvements in gas engines. 

16698. Turner. — Improvements in gas motor engines. 

16890. Regan. — Improvements in or connected with electric igniting appa- 
ratus for gas engines. 

16947. Imray (Barnes & Danks) — Gas motor for tramcar. 

i88 S . 

610. Johnson (Lenoir) Improvements in or connected with gas engines. 

848. Myers. — Improvements in gas motor engines. 
1 2 1 8. Tinkney. —Improvements in governors for gas engines, steam engines, 

and compressed-air engines. 

1363. Simon An improved construction and arrangement of gas engine. 

1424. Asher & Buttress. — A new or improved method of obtaining motive 

power by the explosive combination of sul>stanccs. 
1478. Williamson, King & Ireland Improvements in ignition apparatus 

for gas motors. 
1 58 1. Kcmpster, jun An improve 5 motor driven by the explosion of 

hydrocarbon vapour. 

1700. King Improvements in gas motor engines. 

1703. Wright & Charlton Improvements in heat motors, such improve- 
ments relating to petroleum and other hydrocarbon explosive - 

engines. 
2712. Atkinson. —Improvements in gas engines. 

3199. Beechey Improvements in gas motor engines. 

3414. Spiel. — Improvements in petroleum and gas engines. 
3471. Pope. — Improvements in gas engines. 

3747. Holt Regulator for supply of gas to motor engines. 

3785. Atkinson Improvements in gas engines. 

3971. Mackenzie. — Improvements in gas engines. 

4315. Daimler. — Improvements in motor engines worked by combustible 

gases, or petroleum vapour, or spray. 
4684. Garrett.— Improvements in motors worked by combustible gas or 

vapour. 
5519. Bickerton. - Improvements in gas regulators for supplying gas to gas 

motors. 



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506 The Gas Engine 



NO. 



5561. Andrew. — Improvements in gas motor engines. 

5971. Mills.— Improvements in gas motor engines. 

6047. Rigg.— Improvements in engines worked by elastic or non-elastic 
fluids, or by the explosion of mixed gases ; applicable also to appa- 
ratus for pumping. 

6565. Weatherhogg. — Improvements in gas motor engines. 

6763. McGhee & Magee. — Improvements in gas motor engines. 

6880. Macgeorge. — Improvements in and relating to gas engines. 

6990. Campbell. — Improvements in gas engines. 

7104. Warsop & Hill. —An improved apparatus for igniting the gas or ex- 
plosive mixture in gas motor engines. 

7500. Capitaine & Brtlnler.— Improvements in gas engines. 

7581. Capitaine & UrUnler— Improvements in the production of a com- 
pressed gaseous compound for use in gas motors and for other 
purposes, and apparatus therefor. 

7920. Dawson. - Improvements in gas engines. 

7929. Newton. — Improvements in gas motor engines. 

8134. Crossley. — An improved gas engine. 

8160. Wordsworth & Wolstenholme Improvements in gas engines. 

8411. Humes Improvements in hydro-carburetted air engines. 

8583. Newton Improvements in gas motor engines. 

8584. Treeton. —Improvements in or relating to gas engines. 
8897. Sturgeon Improvements in gas engines. 

9801. Colton (Hartig). — An improved gas engine. 

10227. Priestman & Priestman.— Improvements in the construction and 
working of motor engines operated by the combustion of benzoline 
or other liquid hydrocarbons. 

10401. Justice (Hale).— Improvements in gas engines. 

10786. Daimler.— Improved vehicle propelled by a gas or petroleum motor 
engine. 

1 1290. Redfern (Smyers). — Improvements in gas engines or engines actuated 
by the explosion or combustion of mixed gas or vapour and air. 

1 1 294. Clark (The Economic Motor Company, Incorporated). — Improve- 
ments in gas engines. 

1 1422. Magee Improvements in gas engines. 

HS55. Cattrall & Storet.— Improvements in regulators for gas engines. 

1 1558 Gillott.— Improvements in gas motors. 

1 1933. Abel (Gas-Motoren-Fabrik Deutz).— An improvement in the slides 
and passages of gas motor engines. 

12424. Soutliall.— An improvement in gas motor engines. 

12483. Clark (The Economic Motor Company, Incorporated). — Improve- 
ments in gas engines. 

12S96. Schiltz Improvements in gas and petroleum engines. 

13163. Groth (Daimler). —Improvements in gas and oil motive power engines. 



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Appendix IT 507 



NO. 



15309. Dinsmore.— Improvements in rotary air and gas motor engines. 
13623. Royston. — Improvements in, and in connection with, motive power 

engines actuated by the combustion of a mixture of gas or vapour 

and atmospheric air. 
14394. Nash Improvements in liquid fuel vapour engines and method of 

operating the same. 
14574. Black. —Improvements in the construction of steam and other motive 

power engines of the horizontal and incline and vertical table class. 
15194. Burgh and Gray Improvements in motors actuated by the expansion 

of gases resulting from the combustion of fuel in the motor. 

15243. Atkinson Self-starting valve for gas engines. 

15475. Von Ruckteschell. — An improved explosion engine. 

15525. Ashby. —Improvements in gas engines. 

157 10. Johnson (Deboutteville & Malandin).— Improvements in governors or 

regulators for gas and other motive power engines. 
I 5737« Rogers. — Improvements in gas engines. 
15845. Bickerton. — Improvements in gas motor engines. 

15874. Wilcox Improvements in gas engines. 

15875. Wilcox — Improvements in gas engines. 

15876. Wilcox — Improvements in gas engines. 

15936. Wimshurst.— An improved method of equalising the power given off 
by gas or other engines or motors. 

1886. 

11. Johnson (Deboutteville & Malandin). — Improvements in gas engines. 
207. Butterworth. — Improvements in motors worked by combustible gas 

or vapour. 
478. Fairweather (Babcock) — Improvements in air or gas engines. 
493. Nash. — Improvements in gas engines. 

665. Magee Improvements in gas motor engines. 

942. Brine.— Improvements in gas engines. 
1394. Priestman & Priestman. — Improvements in motor engines operated by 

the combustion of liquid hydrocarbon. 
M33' McGhee. — Improvements in gas engines. 
1464. Humes. — Improved means for mixing and igniting combustible 

charges operating liquid hydrocarbon engines. 
1696. Welch & Rook. — An improved gas engine. 
1797. Shillito (Capitaine).— An improved method and means for cooling the 

cylinders of gas, petroleum, hot air, and similar motors. 
1958. Haddan (Jonasen). — Improvements in gas motors. 
2140. Capitaine & BrUnler.— Improvements in oil, petroleum, naphtha, and 

similar motors. 
2174. Skene. — I mpro vements in gas engines. 



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5o8 The Gas Engine 



NO. 



2272. Leigh (Spiel).— Improved supply valve gear for petroleum or gas 

engines. 
2447. Shaw.— Improvements in the construction of gas engines. 
2653. Boulton & Perrett.— Combined steam and gas engines. 
2993. Mil burn & Hannan. — Improvements in motors worked by combustible 

gas or vapour. 
301a Deacon Improvements in and in connection with motive power 

engines actuated by pressure due to heat of combustion. 
3402. Fielding. —A gas motor engine. 
3473. Davy. — An improvement in gas engines. 
3522. Atkinson.— Improvements in gas engines. 
4234. Niel. — Improvements in gas engines. 
4460. Dawson. — Improvements in gas engines. 

4785. Hutchinson.— Improvements in engines actuated by the thermo- 
dynamic energy of petroleum and similar combustible fluids. 
4881. Justice (Taylor).— Improved combined gas engine and fluid pump. 
5597. Humes.— Improved means for preventing ' back ignition ' in hydro- 
carbon engines. 
5665. Bernardi. — Improvements in and relating to gas engines or motors. 
5789. Benz.— Improvements in gas motors for wheeled vehicles and in their 

application thereto. 
5804. Al>el. — Improvements in gas motor engines. 
6 161. Redfern (Gardie). - An improved motor, and apparatus for generating 

gas therefor. 
6165. Leigh (Spiel). — Improvements in petroleum and gas engines. 
6551. Wright & Charlton Wright.— Improvements in petroleum and such 

like engines. 
6612. Gillespie. — Improvements in gas motor engines. 
6670. Nash. —Improvements in construction and method of operating gas 

engines. 
7427. Rollason.— Improvements in gas engines. 
7658. Nixon.— Improvements in gas engines having two pistons in the 

same cylinder. 
7936. Butterworth.— Improvements in motors worked by combustible gas. 
8210. Roots.— A petroleum engine. 

8436. Weatherhogg. — Improvements in petroleum and similar engines, 
9563. Fielding. — Ignition apparatus for gas motor or oil motor engine. 
9598. Johnson (Deboutteville & Malandin). — Improvements in apparatus 

for carburetting air. 
9866. Stuart. — Improvements in petroleum and other explosive engines. 
10332. Boys & Cunynghame.- Reducing or preventing noise of escaping gas 

or vapour. 
10480. Schiltz. — Improvements in or connected with petroleum motors or 

engines woiked with liquid fueL 



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Appendix II 509 



NO. 



112169. Humes. — Improvements in or applicable to motor engines operated 
by the combustion of fluid hydrocarbon. 

1 1285. Crossley. — Improvements in valves for gas and oil motor engines. 

1 1 576. Bolt. — Improvements in gas engines. 

12068. Hutchinson and Ix>ndon Economic Motor and Gas Engine Co. — Im- 
provements in motor engines worked by combustible gases or 
petroleum vapour or spray. 

1 2 1 34. Butterworth & Butterworth. — Improvements in engines in which power 
is obtained by the ignition and expansion of a combustible mixture. 

12368. Rollason. — Improvements in gas or vapour engines. 

12640. Sutclifie. — Improvements in utilising the waste heat of gas and com- 
bustion explosive motor engines for heating water. 

1 291 2. Clerk. — Improvements in gas motors. 

13229. Humes. — Improvements in and connected with motor engines 
operated by the combustion of fluid hydrocarbon. 

1 35 1 7. Maccallum. — Improvements in and relating to the propulsion of navi- 
gable vessels. 

13655. Rockhill. — Improvements relating to flywheel guards. 

13727. Newton (Murray). — Improvements in the construction of gas engines. 

14034. Daimler.- -Apparatus for effecting marine propulsion by gas or 
petroleum motor engines. 

14578. McGhee. — An improved gas motor engine, specially applicable for 
use with mangling machines. 

15307. Robson. — Improvements in gas engines. 

1 5319. Stuart & Binney. — Improvements in gas, petroleum, and other hydro- 
carbon explosive engines or motors. 

15327. Taylor. — An improved gas motor engine. 

15472. Southall. — An improvement in gas motor engines. 

15507. Wordsworth & Wolstenholme. — Improvements in gas or other 
hydrocarbon motors. 

15507 A. Wordsworth & Wolstenholme. —Improvements in gas or other hydro- 
carbon motors. 

15764. Griffin. — Improvements in apparatus for automatically shutting off* the 
gas supply of gas motor engines. 

x 5955- Hearson. — Improvements in arrangements for utilising the vapour of 
volatile liquid hydrocarbons for actuating motive power engines. 

16779. Priestman & Priestman. — Improvements in the construction and 
working of hydro-carburetted air engines, and in apparatus ap- 
plicable thereto. 

1887. 

8. Turnock.— Improvements in apparatus for converting reciprocating 
into rotary motion, and in the application of such apparatus to steam 
and other fluid pressure engines. 



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5 10 The Gas Engine 



NO. 



125. Sterry & Sterry. — Improvements in explosive gas engines. 

516. Newhall & Blyth. — Improvements in gas and other hydrocarbon 

engines. 
847. Abel (The Gas- Motoren - Fabrik Devtz).— Igniting apparatus for gas 

engines. 
888. Hosack. — Improvements in internal combustion ' heat ' engines. 
1 168. Charter, Gait & Tracy. — Improvements in gas engines. 
1 189. Abel (The Gas-Motoren-Fabrik Deutz). - Improvements in gas motor 

engines. 
1262. Benier. — Improvements in hot air engines. 
1266. Adam. — Improvements in gas and other hydrocarbon engines. 
1454. Priestman & Priestman. — Improvements in the construction and work- 
ing of hydro carburetted air engines. 
1986. Pinkney. —Improvements in hammering, stamping, punching, and 
other like machinery actuated by explosive gaseous mixture. 

2194. Haddan (Gavillet & Martaresche) Improvements in gas engine. 

2236. Bam ford.— Improvements in lubricators used for gas engines and other 

purposes. 
2368. Thomas.— Improvements in engines driven by gas, steam, petroleum, 

and the like. 
2520. Browett & Lindley. — Improvements in motor engines worked by gas 

or hydrocarbon. 
2631. Tellier. — Improvements in tramway and railway locomotives. 
2783. Knight. — Improvements in engines worked by the heavier hydro- 
carbons. 
3109. Spiel. — Improvements relating to engines or motors chiefly designed 

to be driven by means of carburetted air. 
3934. Griffin.— Improvements in the arrangement and construction of gas 

motor engines. 
4160. Beechey. — Improvements in gas-bags or apparatus for regulating the 

supply of gas to gas engines. 
4403. Ross & McDowall. —Improvements in rotary engines and pumps. 
451 1. Ridealgh. — Improvements in gas engines. 
4564. Sington.— Improvements in and relating to the traction or propulsion 

of tramcars and road vehicles by means of gas and similar engines or 

motors. 
4757. Casper (Tavernier).— Improvements in gas and other engines operated 

by explosive mixtures. 
4843. Stevens. — Improvements in combined gas and compressed air 

engines. 
4923. Sturgeon.— Improvements in certain gas engines. 
4940. Wallwork. — Improvements in self-acting mechanism or apparatus for 

supplying lubricant to parts of gas engines and other machinery. 
5095. Johnson (La Societe" des Tissages et Ateliers de Construction Diede- 

richs). — Improvements in gas engines. 



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Appendix II" 511 



NO 



5336. Bernhardt. — Improvements in regulating apparatus for gas motor 

engines. 
5485. Hargreaves.— Improvements in and connected with internal combus- 
tion thermodynamic engines. 
5833. Crossley. — A combined gas motor engine and dynamo electric 

machine. 
5951. Priestman & Priestman. — Improvements in motor engines operated 

by the combustion of liquid hydrocarbon. 
5981. Korting. — Improvements in gas motors. 

6501. Dawson. — Improvements in engines worked by explosive mixtures. 
7350. Faber. — Improvements in gas motors 
7677. Davy. — An improved gas engine. 

7771. Wastfield. — Improvements in and relating to gas engines. 
7925. Wallwork & Sturgeon. — Improvements in gas engines. 
8818. Beechey. — Improvements in gas motor engines. 
91 1 1. Haddan (Archat). — Improvements in gas, petroleum, and other 

hydrocarbon engines. 
9717. Ducretet. —Improvements relating to apparatus for filtering or purify- 
ing oil in connection with gas and petroleum engines. 
10176. Hahn.— Improvements in gas motors. 

10176A. Hahn. — Improvements in carburettors for gas motors and other pur- 
poses. 
10202. H. C. Bull & Co. and H. C. Bull.— Improvements in and connected 

with gas motors. 
10360. Dougill.— Improvements in gas motor engines. 
10460. Griffin. — Improvements in double cylinder gas motor engines. 
1 1255. Justice (Hale). — Improvements in gas and pumping engines. 
1 1345. Lindley & Browett. — Improvements in gas motor engines. 
1 1444. Abel (The Gas-Motoren-Fabrik Deutz). — Improvements in igniting 

apparatus for gas motor engines. 
1 1466. Wordsworth.— Improvements in gas or other hydrocarbon motors. 
1 1503. Abel (The Gas-Motoren-Fabrik Deutz). — Improvements in motor 

engines worked by combustible gas, vapour, or spray and air. 
1 1 567. Niel & Bennett. — Improvements in hydrocarbon engines. 
1 1678. McGhee & Burt. — A new or improved combined mincing machine and 

gas motor engine. 
1 1 71 7. Embleton. — Improvements in gas motor engines. 
1 191 1. Atkinson. — Improvements in gas engines. 
12 1 87. Abel (The Gas-Motoren-Fabrik Deutz).— Improvements in gas motor 

engines. 
12432. Priestman & Priestman. — Improvements in or applicable to meter 

engines operated by the combustion of hydrocarbon vapour. 
12591. Lane. — Improved method of applying or utilising compressed com- 
bustible gases for the production of motive power. 



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5 1 2 The Gas Engine 



NO. 



12592. Hearson. — Improvements in and connected with the vaporisation of 
volatile liquid hydrocarbons, and the utilisation of the vapour 
thereof for actuating motive power engines, and apparatus or 
arrangements for those purposes. 

12696. List, List, & Kosakoff.— Improvements in petroleum engines. 

12749. Charter, Gait, & Tracy Improvements in gas engines. 

12863. Korting. — Improvements in gas engines. 

1 3436. Lea. — Improvements in gas engines. 

13555. Knight Improvements in engines worked by mineral oils. 

13916. Davy. — Improvements in gas engines. 

14027. Barker Improvements in gas engines. 

14048. Middleton. — A new or improved gas motor engine. 

14269. Hutehinson Improvements in and relating to utilising the chamber 

or space between the cylinder and jackets of engines or motors for 
the purpose of vaporising oil in connection with steam, gas, oil, or 
other engines or motors using heat as a source of power. 

14952. Schmid & Bechfeld Improvements in gas engines. 

1 5010. Crossley & Anderson. — Ignition apparatus for gas or oil motor. 

15598. Butler Improvements in hydrocarbon motors, and in the method 

of their application for the propulsion of tricycles and other light 
vehicles. 

15658. Davy. — Improvements in gas and other engines. 

16029. Williams Improvements in gas motor engines. 

16144. Williams. — Improvements in gas motor engines. 

16257. Ravel & Breittmayer. — Improvements in and relating to gas engines, 

16309. Sturgeon — Improvements in gas engines. 

1 7 108. Abel (The Gas-Motoren-Fabrik Deutz). — Improvements in motor 
engines worked by combustible gas. 

1 7353. Wallwork & Sturgeon. — Improvements in apparatus for governing the 
speed of gas engines. 

17686. Bickerton — Improvements in the method of, and apparatus for, start- 
ing gas engines. 

17896. Abel (The Gas-Mctoren-Fabrik Deutz). — Apparatus for heating the 
igniting tubes of gas motor engines. 

1888. 

27a Priestman and another.— Improved means for facilitating the starting 
of hydrocarbon engines, and for regulating the ignition of the in- 
flammable charges whereby same are operated. 

512. Sington — Improvements in gas, petroleum, and similar engines. 

688. Abel (The Gas-Motoren-Fabrik Deutz). — Improvements in igniting 
apparatus for gas motor engines. 
1336. Imray.— Improvements in apparatus for starting tramway •cars. 



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Appendix II 513 



NO. 



1 38 1. Blessing Improvements in gas and other hydrocarbon engines. 

1705. Crossley. — Compound gas or oil motor engine. 

1780. Butler. — Improvements in hydrocarbon motors. 

1 78 1. Butler. — Improvements in hydrocarbon motors. 

2466. Quack. — Improvements in motor engines worked by combustible 
gas or vapour and air. 

2804. Johnson (La Soci&e Salomon). — Improvements in gas engines. 

2805. Johnson ( Deboutteville & Malandin). — Improvements in starting 

gear for gas engines. 
2913. Oechelhaeuser. — Improvements relating to gas engines. 
3020. Abel (The Gas-Motoren-Fabrik Deutz). — Improvements in motor 

engines worked by combustible gas or vapour and air. 
3095. Abel (The Gas-Motoren-Fabrik Deutz). — Improvements in igniting 

apparatus for gas or oil motor engines. 
3427. McGhee & Burt. — Improvements in gas motor engines. 
3546. Rollason & Hamilton. — Improvements in and connected with gas 

and vapour engines. 
3756. Crossley. —Improvements in igniting apparatus for gas and oil motor 

engines. 
3964. Gase. — Improvements in the mode of working gas engines. 
4057. Turner & Brightmore. — Improvements in the application of com- 
pressed atmospheric air to motors. 
4624. Crossley. — An improvement in valve and governing gear for gas or 
' oil motor engines. 

4944. Wilson. — Improvements in or pertaining to combined arrangements 

of gas engines and gas producers. 
5204. Lake (Beuger). — Improvements in and relating to ignition apparatus 

for gas, petroleum, or other engines or motors. 
5628. Tavernier & Casper. — Improvements in and relating to gas and other 

engines. 
5632. Humes. — Improvements in or applicable to motor engines operated 

by the combustion of hydrocarbon vapour. 
5724. Abel (The Gas-Motoren-Fabrik Deutz) An improvement in motor 

engines worked by the combustion of spray of petroleum or other 

combustible liquids. 
5774. Rowden.— Improvements in motors worked by gas or other com- 
bustible bodies. 
5914. Lake (Spiel).— Improvements in and relating to hydrocarbon 

engines. 
6036. Gase. — Improvements in gas engines. 
6088. Thompson (Durand). — Improvements in and relating to engines or 

motors, and to the production of carburetted air for driving the 

same. 

L L 



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5 14 The Gas Engine 



NO. 



6468. Korytynski.— Improvements in engines designed to produce motive 
power through the consumption of inflammable vapours or gas. 

6794. Stitt. — Improvements in or connected with mechanically propelled 
lifeboats, applicable also to other craft. 

7521. Wordsworth. — Improvements in gas or liquid hydrocarbon motor!. 

7547. Browett & Lindley. — Improvements in motor engines worked by 
gas or hydrocarbon. 

7893. Schnell.— Improvements in motor engines actuated by a mixture of 
gas, or the vapour of a hydrocarbon or hydrocarbons, and atmo- 
spheric air. 

7927. Stubbs. — Improvements in motor engines actuated by the combus- 
tion of mixtures of combustible gas and air and the vapour of a 
hydrocarbon or hydrocarbons, or other combustible mixtures. 

7934. Southall.— Improvements in gas motor engines. 

8009. Nelson.— Improvements in hydrocarbon engines. 

8252. Johnston. — Improvements in motors to work with combustible gas or 
vapour. 

8273. Kostovitz. — Improvements in and relating to gas and hydrocarbon 
engines. 

8300. Deboutteville & Malandin. — Improvements in starting gear for gas 
engines. 

8317. Altmann. — Improvements in petroleum motors. 

9249. Deboutteville & Malandin. —Improvements in governors for gas 
engines and other like motors. 

9310. Roots. — Improvements in gas engines. 

931 1. Roots. — Improvements in hydrocarbon engines. 

9342. Aria & Chemin.— Process for treating leather pistons to render same 

impervious to action of petroleum and heavy oils. 
9578. Dougill. — Improvements in gas motor engines. 
9602. Abel (Gas-Motoren-Fabrik Deutz).— Improvements in valve appa- 
ratus for gas and oil motor engines. 
9691. Knight.— Improvements in engines worked by mineral oils. 
9705. Rowden. — An improved motor actuated by the explosions of mixtures 

of inflammable gases or vapours and atmospheric air. 
9725. Middlefon. — Improvements in flying machines, and apparatus for 

propelling the same. 
10165. Purnell. — An improved gas motor engine. 
10350. Nash. — Improvements in gas engines. 
10462. Williams.— Improvements in mechanism for regulating the supply of 

gas or other fluid to gas or similar engines. 
10494. Hall. — Improvements in motor engines operated by the combustion 

of explosive mixtures of fluids. 
10667. Binney & Stuart. —Improvements in petroleum ar.d other hydrocarbon 
explosive engines and motors. 



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Appendix II 515 



NO. 



10748. Campbell. — Improvements in gas motor engines. 

10980. Hargreaves. — Improvements in internal combustion thermo-motors. 

10983. Piers. — An improved form of engine adapted to tramcars and loco- 

motives. 

10984. Piers.— An improved method for starting gas engines and hot air 

and petroleum engines, particularly when such engines are applied 

to tramcars or locomotives. 
1 1067. Roots. — Improvements in hydrocarbon or petroleum engines, 
xi 161. Morris & Wilson.— Improvements in apparatus for the generation of 

gas from hydrocarbon oils. 
1 1 242. Barker. — Improvements in gas engines. 
11614. Purchas & Friend. — Improvements in hydrocarbon motors. 
12361. Hargreaves. — Improvements in internal combustion thermo-motor. 
12399. Charon. — Improvements in gas motors with variable expansion. 
1 3414. Boult (Larrivel & Aeugenheyster). — Improvements in gas motor. 
14076. Stuart & Binney. — Improvements in hydrocarbon explosive engines. 
14248. Crossley, Holt & Anderson. — An improvement in gas motor engines. 
14349. Abel (The Gas-Motoren-Fabrik Deutz).— Igniting apparatus for gas 

and oil motor engines. 
1 4 40 1. Hearson. — Improvements in motive power engines actuated by the 

firing of inflammable gas or vapour in admixture with air. 
14614. Royston. — Improvements in and connected with internal combustion 

heat engines. 
1483 1. Williams. — Improvements in mechanism for governing the speed of 

gas and similar motor engines. 
15158. Richards. — Improvements in hydrocarbon engines, partly applicable 

to other motor engines. 
15448. Thompson (Regan). — Improvements in or relating to gas engines. 
1584a Boult (Capitaine). — Improvements in or relating to gas motors. 
1 5841. Boult (Capitaine). — Improvements in or relating to igniting apparatus 

for gas motors. 

15845. Boult (Capitaine). — Improvements in gas motors. 

15846. Boult (Capitaine). — An improved friction clutch or coupling specially 

applicable to gas motors. 

15858. Jensen (Weil bach). — Improvements in apparatus for braking and re- 
starting of rotating axles or shafts of tramcars, gas engines, and 
other machinery. 

15882. Roots. — Improvements in or connected with petroleum engines. 

16057. Lindley & Browett.— Improvements in liquid hydrocarbon motor 
engines. 

16 1 83. Simon. — An improvement in or connected with gas engines. 

16220. Roots. — Improvements in gas engines. 

16268. Lalbin. — Improvements in and relating to gas engines. 

16605. Menzies.— Improvements in and relating to piston packing rings. 

LL2 



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5i5 The Gas Engine 

NO. 

1 7 167. Korting. — Improvements in gas and petroleum engines. 

1 74 1 3. Crossley & Anderson. — Improvements in igniting apparatus for gas or 

oil motor engines. 
18377. Shaw. — Improvements in gas and other explosive engines. 
18761. Hargreaves. — Improvements in internal combustion thermo- motors. 
1 901 3. Finkncy. — Improvements in gas motor engines. 

1889. 
221. Boult (Capitaine). — Improvements in or relating to distributing 

mechanism for gas motors. 
441. Paton. — Improvements in appliances for starting gas and similar 

engines. 
708. Taylor. — An improved gas motor engine. 
875. Repland (Niel). — Improvements in gas engines. 
1603. Tavernier. — Improvements in and relating to engines. 
2957* Publis. — Improvements in gas motors. 
2144. Piers. — The application of gas and petroleum and like engines to 

locomotive and other intermittent work. 
2637. Miller. — Improvements in and relating to petroleum, oil, vapour, 

gas, and other explosive power engines. 
2649. Gardie. — An improved gas engine and gas generator therefor. 
2760. Hartley. — Improvements in apparatus for measuring liquids. 
2772. Smith. — Improvements in or relating to the starting of motive power 

engines. 
3331. Adams. — Improvements in engines and motors actuated by products 

of combustion. 
3525. Pinkney.— Improvements in gas engines. 
3820. Williams. —Improvements in gas motor engines. 
38^7. Imray ( Weil bach ). — Improvements in brake apparatus for revolving 

axles or shafts. 
3972. Roots.— Improvements in gas engines. 

4710. Oechelhaeuser.. — Improvements in and relating to gas engines. 
4796. Schimming. — Improvements in, and apparatus for, superheating steam 

and applying the same to steam engines. 
5072. Southall. — Improvements in gas or oil motor engines. 
5165. Lake. — Improvements in and relating to gas or vapour engines for 

the propulsion of ships and other purposes. (The Secor Marine 

Propeller Company.) 
5199. Millet. — Improvements in gas and other fluid pressure engines for 

terrestrial and aerial propulsion. 
5301. Theerman. — Improvements in motor engines operated by the ignition 

of explosive mixtures of air and petroleum, or other hydrocarbon, 

or gas. 
5397. Nelson & McMillan. —Improvements in gas motor engines. 



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Appendix II 517 



vo. 



5616. Abel (Gas-Motoren-Fabrik Deutz).— Improved mechanism for revers- 
ing the motion derived fiom a motor shaft, applicable to the motor 
engines of vessels and vehicles, and for other purposes. 
6i6r. Partridge & Brutton.— Improvements in means or apparatus for start- 
ing gas and other engines and machines. 
6296. Banki & Csonka — Improved valve motion for gas engines. 
6682. Priestman and another. —Improvements in or applicable to motor 

engines operated by the combustion of hydrocarbon vapour. 
6748. Cord enons. — Improvements in rotary engines. 
6831. Knight. — Improvements in engines worked by mineral oils. 
7069. Tavernier & Casper. —Improvements in and relating to engines 

worked by explosive mixtures. 
714a Tellier — Improvements in the production of motive power by the 
employment of gas, steam, and vapour, and in apparatus employed 
therefor, and for its utilisation. 
7522. Sumner.— An electric ignition apparat us for gas, petroleum, oil, or 

combustible vapour engines. 
7533. Sumner. —An ignition apparatus for gas, petroleum, oil, or combusti- 
ble vapour engines. 
7594- Crowe & Crowe.— Improvements in gas and hydrocarbon motive 

engines. 
7640. Lawson. — Improvements in gas engines. 
8013. Wcatherhogg. — Improvements in and relating to petroleum and 

similar engines. 
8778. Imray (Glaser).— Improvements in petroleum motor engines. 
8805. Clerk. — Improvements in gas engines. 
9203. Butler and others. — Improvements in and connected with motors in 

which an explosive mixture of air and petroleum is used. 
9685. Hunt & I lowden.— Improvements in motors actuated by combusti- 
ble gas or vapour. 
9834. Roots.— Improvements in petroleum or hydrocarbon engines. 
10007. Daimler.— Improvements in gas and petroleum motor engines. 
10286. Rogers & Wharry. — Improvements in gas engines. 
10634. Bull. — Improvements in petroleum and other explosive vapour or gas 

engines. 
10669. Rowden. — Improvements in gas motors. 

1083 1. Leigh (Forest & Gallice).— Improvements in compound gas or petro- 
leum engines. 
10850. Wast field. — Improvements in or relating to petroleum or hydro- 
carbon engines. 
1103S. White & Middleton. — Improvements in gas engines. 
1 1 162. Williams. — An improved incandescent tube for firing the explosive 

charges of gas and other similar motor engines. 
11395. Hartley.- Improvements in hydrocarbon or petroleum engines. 



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5i8 The Gas Engine 



NO. 



X 1926. Bull. —Improvements in vapour gas engines. 

12045. Allison (McNett).— Improvements in combined gas engines and 

carburetters. 
I2447. Hoelljes. — Improvements in, and in tbe method of operating, gas 

engines. 
12472. Thompson (Covert).— Improvements in or relating to gas engines or 

gas motors. 
12502. I^an Chester.— Improvements in apparatus for governing gas and other 

motive power engines. 
13572. Mc Allen. — Improvements in gas or oil motor engines. 
14592. Huntington.— Improvements in vehicles. 
14789. Hargreaves. —Improvements in internal combustion regenerative 

thermo-motors, some of which said improvements are applicable to 

gas and hot air engines. 
1486S. Binney & Stuart. - Improvements in hydrocarbon engines. 
14926. Diederichs. — Improvements in or connected with combustible vapour 

engines. 
16202. Green. — Improvements in gas engines. 
16391. Lindemann. — Improvements in gas and petroleum engines. 
16393. Girardet.— Improvements in means for generating and utilising gas 

or vapour, and in apparatus therefor. 
16434. Hamilton & Kollason. — Improvements in and connected with gas or 

vapour engines. 
1700S. Haedicke. — A combined gas and steam motor engine. 
17024. Boult (Rotten). —Improvements in petroleum or similar motors. 
17295. Kiel & Janiot.— Improvements in gas motors. 
17344. Lowne — Improvements in atmospheric engines, partly applicable to 

other motive power engines. 
18746. Abel (The Gas-Motoren-Fabrik Deutz).— Improvements in igniting 

apparatus for gas and oil motor engines. 
18847. Barnett & Daly.— Improvements in gas or vajiour engines, and in 

electric exploding devices, or apparatus for such engines. 
19868. Lanchester. — Improvements in gas motor engines. 
20033. Lindley & Browett. — Improvements in hydrocarbon motor engines. 
201 15. Ford Improvements in rotary gas engines, parts of which improve- 
ments are applicable to other engines. 
20161. Duerr.— Improvements in gas and petroleum motors. 
20166. Frederking and another — Improvements in positive motion gear for 

lift valves. 
20249. Crist & Covert.— Improvements in gas engines and igniters for the 

same. 
20482. Atkinson.— Improvements in internal combustion heat engines, 
20703. Snelling.— Improvements in rotary engines to work with steam, air, 

gas and other fluids. 



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Appendix II 519 



NO. 



20892. Abe (The Gas-Motoren-Fabrik Deutz). —Improved apparatus for 
regulating the speed of gas and oil motor engines. 

1890. 
1 1 50. Lindner. — Improvements in or connected with petroleum engines. 
1586. Ta vernier & Casper.— Improvements in or relating to the cylinders 

and pistons of engines operated by explosive mixtures. 
1943. Abel (The Gas-Motoren-Fabrik Deutz) Improvements in motor 

engines worked by oil vapour. 
2207. Scollay Improved means for regulating the admission of gas and 

air in atmospheric burners, and for supplying gas engines. 

2^84. La Touche Improvements relating to hot air engines. 

2647. Lake (Beckfield & Schmid).— Improvements in gas engines. 

2919. Grob and others. — Improvements in petroleum engines. 

4164. Abel (Gas-Motoren-Fabrik Deutz). — Improvements in the means 

and apparatus for governing gas and petroleum engines. 
4362. Binns. — Improvements in gas motor engines. 
4574. Kaselowsky.— Improvements in gas and petroleum motors. 
4823. Otto.— Improvements in gas or oil motor engines. 
5005. Baxter (Hoist). — Improvements in gas engines. 
5192. Melhuish. — Improvements in gas and petroleum motors. 
5273. Otto. — Improvements in gas or oil motor engines. 
5275. Otto. — Improvements in petroleum or oil motor engine 
5479. Lanchester. — Improvements in gas motor engines. 
5621. King (Connelly). — Improvements in or connected with driving gear 

for giving motion to tramcars and other vehicles propelled by 

motors. 
5933. Dheyne and others. —Improvements in gas engines operated by gas 

generated from petroleum or other liquid hydrocartxms. 
5972. Otto. — Improvements in gas and oil motor engines. 
601 5. Hamilton. — Improvements in gas or combustible vapour motor 

engines. 

61 13. Otto Improvements in gas and oil motor engines. 

6217. Griffin Improvements in apparatus for producing combustible gas 

for gas motor engines or other purposes. 
6407. Dawson. — Improvements in gas engines. 

6910. Dorrington & Coates Improvements in gas engines. 

6912. Fielding Improvements in gas motor engines. 

6990. Butler Improvements in motive engines operated by explosive mix- 
tures of petroleum and air. 
7146. Stuart & Binney. —Improvements in engines operated by the explosion 

of mixtures of combustible vapour or gas and air. 
7177. Mewburn (Proell and others).— Combined gas and compressed air 

motors. 



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520 Tlie Gas Engine 



NO. 



7626. Johnson (Lantsky). — Improvements in engines or motors actuated by 

products of explosion or combustion. 
8431. Seage & Seage. — Improvements in gas motor engines. 
9496. Rotison Improvements in gas or other motive power engines. 

10051. Wilkinson Improvements in apparatus for producing hydro- 
car buretted air for motive power purposes. 

10089. Beechey. — Improvements in gas motor engines. 

10642. Vogelsang & Hille — Improvements in valve gear of gas engines and 
petroleum engines. 

1 07 1 8. G rob and others. — Improved means for effecting the igni tion of vapour 
in gas and petroleum motors. 

10952. Griffin Improvements in apparatus for regulating and governing 

the admission of gas and air into gas motor engines. • 

1 1062. Lake (Brayton) Improvements in hydrocarbon engines. 

1 1 755. Richardson & Norris — Improvements in gas or vapour engines. 

1 1834. Schiersand. — An improved spring governor or regulator for gas and 
other engines and motors. 

1 23 14. Holt.— An improvement in supply, exhaust, and governing apparatus 
for oil motor engines. 

12472. Stuart. — Improvements in compound hydrocarbon explosive engines. 

12678. Justice (Baldwin).— Improvements in tramcars and motors. 

12690. McGhee & Burt. — Improvements in and relating to gas motor 
engines. 

12760. Stallaert. — Improvements in motors adapted to be operated by ex- 
plosives. 

13019. Vermand Improvements relating to gas engines. 

1 305 1. Stuart. — Improvements in rotary motors. 

13352. Ovens & Ovens. — Improvements in gas engines. 

'3594- Offen. — Improvements in gas and other explosive engines. 

14382. Hall. —Improvements in igniting arrangements for gas or oil motor 
engines. 

14549. Roots.— Improvements in gas engines. 

14787. Robinson.— Improvements in gas or combustible vapour engines. 

14900. Detxmtteville & Malandin. — Improvements in or connected with gas 
engines. 

I 53°9- Hartley. — Improvements in hydrocarbon or petroleum engines. 

15525. Dheyne and others. — Improvements in apparatus for use in connection 

with engines operated by gas generated from petroleum or other 
liquid hydrocarbon. 

15526. Dheyne.— Improvements in engines operated by gas generated from 

petroleum or other liquid hydrocarbon. 
15994. Stuart & Binney. — Improvements in or connected with engines 
operated by the explosion of mixtures of combustible vapour, or gas 
and air. 



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Appendix II 52 1 



NO. 



16301. Cruikshank (White & Middleton). — Improvements in gas engines. 
17 167. Pinkney Improvements in and connected with engines operated by 

gas generated from petroleum or other liquid hydrocarbons. 
17299. Mottershead. — Improvements in or connected with gas engines. 
1737 1. Higginson. -Improvements in gas engines. 
18161. Sayer. — Improvements in gaseous pressure apparatus for producing 

continuous rotary or rectilinear motion. 
1 840 1. Griffin. — Improvements in apparatus for igniting the charge in 

petroleum and other hydrocarlxm motors. 
18645. Boult (Sharpneck). — Improvements in gas engine governors. 
191 7 1. Kaselowsky. — Improvements in ignition devices for gas motors. 
19513. Lanchcster Improvements in the igniting and starting arrangements 

of gas and hydrocarbon engines. 

19559. Roots Improvements in petroleum or liquid hydrocarbon engines. 

19775. Lanchester. — An improved ignition device for starting gns motor 

engines. 
19791. Lol>et. —Improvements in gas and other motive power engines. 
19846. Lanchester.— Improvements in uniting and starting gear for gas 

engines. 
19962. Griffin. — Improvements in petroleum and other liquid hydrocarlxjn 

motors. 
20S88. Holt. -Improvements in motor engines worked by gas, or by oil or 

other vapour. 
21 165. Lentz and others. — A single-acting gas motor engine. 

1891. 

103. Pinkney. — Improvements in and connected with engines operated by 
gas generated from petroleum or other liquid hydrocarbon. 

no. Carling.— An improvement in gas engines and other like motors. 

191. Gray Improving engines actuated by the explosion of a mixture of 

air with the vapour of petroleum or other hydrocarlxms, or of tar, 
creosote, or other liquid, which when heated are more or less vola- 
tile, and the vapour of which, when mixed with air, forms an ex- 
plosive mixture. 

227. Bickerton Improvements in gas engines. 

297. Bickerton. — Improvements in governors for gas engines. 

383. Boult (Berliner Maschincnbau Actien Gesellschaft).— Improvements 
in or relating to the valve gear of gas, petroleum, and other similar 
engines. 

741. Adams. — Improvements in engines, motors, and pumps. 

816. MacCallum. — Improvements in gas, petroleum, and like engines. 

834. Miller.— Improvements in petroleum, oil, vapour, gas, and other 
explosive power engines. 

970. Williams. — Improvements in gas motor and similar engines. 



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522 The Gas Engine 



NO. 



1083. Robinson. — Improvements in gas or combustible vapour engines. 
1299. 'Williams — Improvements in gas motor engines. 
1447. Weatherhogg. — Improvements in gas and hydrocarbon motor engines. 
1903. Abel (Gas-Motoren-Fabrik Deutz). — Improvements in gas and oil 

motor engines. 
2053. Gray.— Improvements in vaporisers for generating petroleum and 

other hydrocarbon vapours for use in motors and engines. 
2815. Rouzay. — Improvements in gas or petroleum engines. 

2976. Hughes (Cordenons) Improvements in gas engines. 

3261. Weiss. — Improvements in petroleum or oil motor engines. 

3350. Coffey. — An improved gas engine. 

3669. Rockhill. — An improved gas engine. 

3682. Wertenbruch. — Improvements in or connected with gas and other 

hydrocarbon engines and the pistons (or rings) thereof. 
3830. Priestman & Priestman. — Improvements in or applicable to hydro- 

carburetted air engines. 
3948. Trewhclla. — Improvements in apparatus for condensing and utilising 

the residue of gases exploded to form a vacuum in engines propelled 

by gas or other explosive material. 
4004. Dawes. — A new or improved apparatus to be used for the starting of 

gas or other engines. 
4142. Priestman & Priestman. — Improvements in hydro-carburetted air 

engines. 
4222. Lanchester. — Improvements in gas engines. 
4355. Campbell. — Improvements in gas motor engines. 
4535* Griffin. — Improvements in governing gas motor engines and in con- 
nection therewith. 
4771. Cooper. — Improvements in gas and vapour engines. 
4862. Lindemann. — Improvements in gas and petroleum engines. 
5158. Vanduzen. — Improvements in gas and gasoline engines. 
5250. Love & Priestman Bros., Ltd. — Improvements in or applicable to 

motor engines operated by the combustion of hydrocarbon vapour 

or gas and by the expansion of readily liquefying gases. 
5490. Higginson. — Improvements in gas engines. 

5663. Fachris. — An improved motive power engine, actuated by explosives. 
5747. Skene. — An improved fluid pressure regulator. 
6090. Bickerton. — Improvements in gas motor engines. 
641a Day. — Improvements in gas engines. 

6578. Barclay Improvements in and relating to gas engines. 

6598. Ridealgh & Welford. — Improvements in gas or vapour engines. 
6717. Abel (The Gas-Motoren-Fabrik Deutz). — Improvements in apparatus 

for supplying oil or other liquids under a constant head or pressure. 
6727. Van Rennes. —Improvements in petroleum engines. 



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Appendix II 523 



NO. 



6949. Key. — Improvements in and relating to the treatment of the discharge 
gases from gas engine cylinders. 

7047. Purnell A governor for gas and oil motor engines. 

7157. Altmann.— Improvements in governors for gas and petroleum motors. 

7313. Pinkney Improvements in engines worked by the explosion of gas» 

8032. Horn (Vanduzen & Vanduzen). — An improved gas engine. • 

8069. Capitaine.— Improvements in gas motors. 

8251. Barrett & Ticehurst. — Improvements in motor engines actuated by 

explosions. 
8289. Hardingham (Clefand). — An improved rotary engine. 
8469. Abel (Gas-Motoren-Fabrik Deutz). — Improvements in gas and oil 

motor engines. 
8821. Shillitto (Grob, Schultze & Niemczik). — Igniting tubes for gas and 

petro'eum motors. 
9006. Boult (Levasseur).— Improvements in gas, petroleum, and carburetted 

air engines. 
9038. Southall. — Improvements in gas and oil motor engines. 
9247. Day. — Improvements in gas or vapour engines. 
9268. Bosshardt (Huntington) — Improvements in governors and valve 

movements for gas engines. 
9323. Huelser (J. M. Grob & Co.). — A new or improved gasifying con- 
trivance for petroleum motors. 
9805. Hawkins. — Improvements relating to vibrating engines, applicable to 
pumps or blowers. 

9865. Dawson Improvements in gas engines. 

9931. Withers & Covert. — Improvements in or relating to vibrating gas 

engines. 
10298. Crossley & Holt. — Improvements in oil motor engines. 
10333. Fiddes & Fiddes.— Improvements in gas motor engines. 
11 132. Irgens. — Improvements in and relating to gas or petroleum engines 

or motors. 
1 1 138. Pinkney. — Improvements in or connected with engines worked by 

gas generated from petroleum or other liquid hydrocarbon. 
1 1628. Held. — A new or improved pressure regulator for gas engines. 
1 1680. Kasclowsky. — Improvements in gas and petroleum engines. 
11851. Wellington. —An improved ignition tube for gas and like engines. 
1 1861. Lanchester. — Improvements in gas engine starting arrangements. 
12330. Settle. — Improved means for actuating road or tram cars and lake or 

other boats. 
1 241 3. Clerk. — Improvements in gas engines. 
1 298 1. Menard.— Improved method and means for firing the charges of gas 

engines. 
14C02. King (Connelly). — Improvements in gas motors. 



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524 The Gas Engine 



NO. 



14 1 33> Weyman 5c Drake.— Improvements in governing and regulating the 
supply of oil to petroleum or hydro-carl on motors. 

14 1 34. Watkinson. — Improvements in thermo-dynamic machines and in 

apparatus and appliances connected therewith. 
14209. Johnson (Genty). — Improvements in non-return valves. 
14269. Huelser (Grob & Co.).— Improvements in gas and peiroleum motors. 

14457. Waller. — An improved apparatus for exhausting gas. 

14519. Abel (Gas-Motoren-Fabrik Deutz). — Improvements in igniting appa- 
ratus for gas and oil motor engines. 

14945. Lanchester. —Improvements in gas governors. 

15078. Williams. — Improvements in gas and similar motor engines. 

16404. Clerk.— Improvements in gas engines. 

17033. Shiels. —Improvements in apparatus for automatically regulating the 
temperature of the water used in cooling the cylinders of gas and 
oil engines. 

17073. Ilornsby & Edwards. — Improvements in explosion engines. 

17364. Evers Improvements in gas motor engines. 

17724. Abel (Gas-Motoren-Fabrik Deutz).— Improvements in valve appa- 
ratus for gas and petroleum motor engines. 

17815. Evans. —Improvements in gas engines. 

17955. Pinkney. — An improved metallic alloy more especially intended for 
use for gas or petroleum engine igniters, or like articles subjected 
to great heat. 

18020. Shaw & Ashwor h Improvements in gas engines. 

18276. Walch (Dorrington & Coates) Improvements in valve gears for gas 

engines. 

18424. Lee. — Improvements in gas and hydrocarbon motor engines. 

18621. Roots & Seal — Improvements in or connected with internal com- 
bustion engines. 

18640. Weyman, Hitchcock & Drake.— Improvements in gas and oil hydro- 
carbon engines. 

187 1 5. Earnshaw & Old field — Improvements in and connected with valves 
of gas engines. 

18788. Clerk. —Improvements in starting gear for gas engines. 

19086. McGhee & Burt. — Improvements in and relating to gas motor 
engines. 

19275. Roots — Improvements in petroleum or liquid hydrocarbon engines. 

1 93 1 8. Barron — Improvements in or appertaining to gas engines. 

1 95 1 7. Fielding. — An improved method of smarting gas engines. 

I0 77 2 « Johnson (Picper). — Improvements in feed pumps for petroleum 
engines. 

'97 73' Johnson (Pieper). — Improvements in the means for regulating the 
temperature of evaporators of petroleum engines. 

19811. Ridealgh.— Improvements in gas and petroleum engines. 



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Appendix II 525 



NO. 



20262. Robinson Improvements in gas or combustible vapour engines. 

20745. Robinson. —Improvements in gas or combustible vapour engines. 

20845. Perrollaz. — Improvements in lubricators. 

20926. Knight.— Improvements in engines worked by heavier hydrocarbons. 

21015. Weyman, Hitchcock & Drake. — Improvements in oil or hydro- 
carbon motors. 

21229. Weyman, Hitchcock, & Drake.— Improvements relating to oil or 
hydrocarbon motors. 

21406. Lanchester.— Improvements in gas engines. 

21496. Hartley & Kerr. - Improvements in gas engines. 

21529. Miller. — Improvements in valve gear for gas and other engines. 

22559. J-eigh (Forrest & Gallice). — Improvements in gas and petroleum 
engines. 

22578. Burt.— New or improved starting, stopping, and reversing gear for 
machinery driven by gas or vapour engines. 

22834. Seek. — Improvements in gas and hydrocarbon engines. 

22847. Abel (The Gas-Motoren-Fabrik Deutz). — Improvements in petroleum 
or oil motor engines. 

1892. 

112. Richardson.— Improvements in the details of gas and vapour 

engines. 
260. Edwards (Petit & Blanc). — Improvements in the means of heating 
the charge in gas and like engines. 

520. Higginson Improvements in gas engines. 

524. Wilkinson. — Improvements in the working of gas engines. 
826. Rankin & Rankin. — Improvements in petroleum and other hydro- 
carbon motors. 
919. Noble & Brice.— Improvements in lubricators for use in connection 

with gas, oil, or other explosive engines. 
926. Simon. — Improvements connected with gas and like engines. 
1203. Sou thall.— Improvements in supply and discharge valves for gas or 

oil motor engines. 
1246. Brooks & Holt— Improvements in or additions to gas and vapour 

engines or motors. 
1768. Richardson & Norris. — Improvements in gas engines. 
1814. Schwarz. — An improvement in or connected with gas engines. 
1879. Barker & Rollason. — Improvements in and appertaining to gas-bags 

for gas engines. 
2 1 81. Atkinson. —Improvements in self-starting apparatus for gas and other 

internal combustion motors. 
2492. Atkinson.— Improvements in internal combustion engines. 
2495. Swiderski. — An improved oil or gas motor. ' 



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526 The Gas Engine 

NO. 

2728. Abel (Gas-Motoren-Fabrik Deutz). —Improvements in gas or oil motor 
engines. 

2854. Leigh (Spiel). — Improvements in liquid hydrocarbon engines. 

2862. Crossley & Bradley. — Improvements in starting and igniting appa- 
ratus for gas or oil motor engines. 

3047. Instone An improved oil or gas engine. 

3156. Bradford. — Improvements in fluid pressure motive power engines. 

3165. Harris.— Improvements in tubes and apparatus for igniting gas, 
petroleum and vapour engines by intermolecular combustion. 

3203. Pinkney. — Improvements in or connected with gas engines. 

3292. Czermak, Bergl, & Hutter Improvements in gas motor engines. 

3417. llumpidge, Humpidge, & Snoxell. — Improvements in gas motor 
engines. 

3574. Robert. — Improvements in and relating to gas engines. 

3909. Stuart & Binney. — Improvements in hydrocarbon engines, 

4078. Bickerton Improvements in governors for gas engines. 

41F9. Hamilton. — Improvements in gas motor engines. 

4210. Lanchester. — Improvements in gas engine details. 

4347. Bell & Richardson — Improvements in portable petroleum or liquid 
fuel engines. 

4352. Richardson & Norris. — Improvements in and appertaining to combus- 
tion chambers of petroleum or hydrocarbon engines. 

4374. Lanchester.— Improvements in gas and petroleum engines. 

4375. Richardson & Norris. — Improvements in the oil-supplying arrange- 

ments of petroleum and other hydrocarbon or liquid fuel engines. 
5445. Clerk. — Improvements in gas engine governors and valve gear. 
5740. Bilbault. — Improvements in and relating to gas and petroleum 

engines. 
58 19. Michels (Grob & Co. ) — Improvements in feeding devices for petroleum 

motors. 
5972. Bell & Richardson Improvements in semi-portable petroleum or 

liquid fuel engines. 
6240. Owen. — Improvements in motors to be operated by either gas or liquid 

hydrocarbons. 
6284. Chattcrton. — Method according to which steam and afterwards gas 

are used as working fluids in the same cylinder for the generation 

of power. 
6655. Morani. — Improvements in gas motors. 
6828. Adams. — Improvements in rotary engines, motors and pumps. 
6872. Shillito (Swiderski & Capitaine). — An improved petroleum motor. 

6952. Dawson Improvements in gas engines. 

7047. Courtney (Briienler) — Improvements in petroleum engines. 

7241. Diesel. — A process for producing motive work from the combustion 

of fueL 



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Appendix II 527 



NO. 



7943. Sennett & Dune. — Improvements in the methods connected with the 
production of supply of steam and gases, and in the utilisation there- 
of in engines for producing motive power, and in the apparatus 
therefor. 

8128. Hornsby & Edwards. Improvements in engines actuated by the 
explosion of combustible mixtures. 

8401. Pollock. — Improvements in gas engines. 

8538. Beugger. — Improvements in or applicable to gas and hydrocarlx)n 

engines. 
8678. Johnson (Genty).— Improvements in furnace gas engines or aero- 
thermic motors. 

^733' Griffin. — Improvements in or in connection with heating the igniting 
apparatus of petroleum or other liquid hjdrocarbon engines. 

91 2 1. Guillery. — An improved rotary motor, applicable also for use as a 
pump, ventilator, or the like. 

916 1. Robinson. — Improvements in gas or combustible vapour engines. 

9439. Beugger Improvements in petroleum and gas motors. 

9448. Ogle. — Improvements in the means for igniting the charges in the 
cylinders of explosion engines. 

9674. Magee. — Improvements in gas motor engines. 

10091. Seek. — Improvements in or connected with hydrocarbon motors. 

10254. Hamilton. — Improvements in valve operating and governing me- 
chanism of gas and oil motor engines. 

10437/ Holt An improvement in igniting apparatus for gas and oil motor 

engines. 

11X41. Weyman, Hitchcock, & Drake. — Improvements in hydrocarbon 
motors and in apparatus and appliances connected therewith. 

11598, Thompson (O' Kelly). — Improvements in or relating to tramcars and 
in motors therefor. 

U708. Hitchcock & Drake. — Improvements in oil engines and the like 
hydrocarbon motors. 

1 1 928. Webb. — Improvements in gas engines. 

1 1936. Clerk. — Improvements in starting gear for gas and like engines. 

11962. Hornsby, Edwards & Gibbon. — Improvements in engines actuated 
by the explosion or burning of combustible mixtures. 

1 2165. Anderson. — Improvements in gas and oil motor engines. 

1 2183. Boult (Charter). — Improvements in gas or similar engines. 

13077. Davy. — Improvements in gas engines. 

13088. Johnson (Hille). — Improved mixing valve for petroleum and like 
motors. 

131 17. Clerk An improved method of operating, and improvements in, 

gas or petroleum hammers, gas pumps, gas punching, riveting 
or cutting machines, in part applicable to gas or petroleum 
engines. 



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528 The Gas Engine 



NO. 



13204. Abel (Gas-Motoren-Fabrik Deutz). — Improvements in gas and oil 

motor engines. 
13859. Binns. — Improvements in gas engines. 

13939. Sayer. — A gas or similar motor for stationary or locomotive purposes. 
143 1 7. Von Oechelhauser & Junkers. — Improvements in and relating to gas 

engines. 
14650. Ilo^g & Forbes.— Improvements in hydrocarbon engines. 
14713. De Susini. — Improvements in motor engines worked by either vapour 

or other volatile fluids in combination with a gas motor engine for 

the utilisation of the waste heat thereof. 
15247. Piers. — Improvements in gas engines. 
1 54 1 7. Weyman Improvements in and connected with petroleum and like 

engines. 
16308. May bach. — Improvements in the method of, and the apparatus for, 

effecting a continuous circulation and cooling of liquids employed 

in motors and compressors. 
16339. Griffin. — Improvements in liquid hydrocarbon and other motor 

engines. 
16365. Briggs & Sanborn. — An improved lubricating cup. 

1 6379. Briinler. — Petroleum motor contrivance for pressing the petroleum into 

the gasificator by means of the air current introduced for the forma- 
tion of the mixture. 

16380. Briinler. — Improvements in rotating petroleum motors. 

1 638 1. Briinler. — Petroleum motor. 

163S2. Briinler. —Improvements in evaporating devices for cooling gas and 
petroleum motors, the cylinders and pistons of which are rotating 
round a stationary crank. 

1 64 1 3. Red fern (La Societe Anonyme des Moteurs Thermiques Gardie).— 
Improvements in and connected with gas engines or motors. 

169S6. Whittaker. — Improvements in and connected with ignition tube for 
gas engines. 

1 7277. Andrew, Bellamy & Garside Improvements in apparatus for govern- 
ing the speed of gas, oil and other similar motor engines. 

17391. Fairfax (Sbhnlein).— Improvements in petroleum motors. 

17427. Hartley & Kerr. — Improvements in compound engines, and in part 
applicable to other gas engines. 

17632. Held. — Improvements in petroleum and like engines, applicable to 
fire extinguishing and other purposes. 

1 7732. Paton. — Improvements in gas engines. 

18020. Southall. — Improvements in gas and oil motor engines. 

18109. Southall Improvements in gas and oil motor engines. 

1 81 18. Gilbert -Russell. — Improvements in explosion engines. 

18513. Cock.— An improvement in gas engines. 



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Appendix II 529 



NO. 



18808. Stroch.— Improvements in or connected with petroleum or other 

hydrocarbon motors. 
2008S. Dowie & Handyside. — A gas engine governor gear. 

20413. Ryland Improvements in explosion engines. 

20660. Weyman & Ellis. — Improvements in utilising the heat taken up by 

the water employed for cooling the cylinders of gas, oil, or other 

hydrocarbon motors. 
20683. Tinkney. — Improvements in gas engines. 

20802. Andrew & Bellamy — Improvements in gas, oil, and similar motor 

engines. 

20803. Andrew & Bellamy.— Improvements in gas, oil, and similar motor 

engines. 

21342. Priestman & Priest man.— Improved means for facilitating the start- 
ing of hydro-carburet ted air engines. 

21475. Enger. — Improvements in gas engines or motors. 

21534. Altmann. — Improvements in and connected with spray apparatus for 
hydro-carburetted air engines. 

21857. Winckler (Jastram).— An improved arrangement for feeding oil 

engines with oil in a duly regulated manner. 

21858. Winckler (Jastram) An improved reversing gear for a propeller 

worked by engine power, with a reversing counter-shaft revolving 
in an opposite direction to the main shaft. 

21917. Wetter (Rademacher). — Process and apparatus for igniting the com- 
bustible charges or gas mixtures of gas and oil motcrs. 

21952. Diirr.— Improvements in hydrocarbon engines. 

22664. Stuart h. Binney — Self-starting mechanism for hydrocarbon engines. 

22797. Weyman, Hitchcock, & Drake — Gear for transmitting and revers- 
ing the power given off by gas and oil motor engines. 

23323. Knight. — Improvements in oil and gas engines. 

23786. Roots Improvements in or connected with internal combustion 

engines. 

23800. Sennett & Durie. — Improvements in the methods and means of 
cooling, heating, and lubricating cylinders, such as those of gas 
and steam engines, air compressors, and the like, and of equalising 
the motion of the piston therein. 

24065. Best. — Improvements in gas engines and in their application to motor 
vehicles. 

1893. 

108. Fielding. — An improved double-cylinder gas or oil motor engine. 
153. Wetter (Gerson & Sachse). — Method of varying the strength of the 

explosion charge or the ratio between the constituents of the gas 

and air mixture in gas engines. 

M M 



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530 The Gas Engine 



NO. 



531. Shut lie worth and others. — Improvements in furnace lamps for oil 

and gas engines. 
608. Saliatier and others. — Improvements in gas and petroleum engines. 
735. Abel (Gas-Motoren-Fabrik Deutz). — Improvements in gas and oil 

motor engines. 
779. Shiels Improvements in apparatus for automatically regulating the 

temperature of the water used in cooling the cylinders of gas and 

oil engines. 
1070. Dawson. — Improvements in gas engines. 

1277. Burt & McGhee Improvements in and relating to gas or ex- 
plosive vapour motor engines. 

21 10. Dixon An improvement or improvements in gas engines. 

2523. Mellin & Reid Apparatus for deodorising the exhaust of gas or 

oil motor engines. 
2596. Lanyon (Martin). — An improved hydrocarbon motor. 

2788. Evans Improvements in gas engines. 

2851. Bellamy Improvements in gas and similar motor engines. 

2912. Weyman. — Improvements in or connected with lamps and vaporisers 

for oil engines. 
3332. Hartley & Kerr.— Improvements in gas engines. 
3401. Davy. — Improvements in gas engines or other internal combustion 

engines. 
3971. Hartley & Kerr — Improvements in compound gas and like engines. 
4327. Ileys (Langensiepen) A new or improved admission valve for gas 

or o 1 engines 
4564. Bellamy.- Improvements in gas and similar motor engines. 
4696. Davy. — Improvements in gas and other internal combustion engines. 
5005. Rollason. — A device for preventing the bursting of gas engine and 

other water-jacketed cylinders or pipes by the freezing of the 

water. 

5256. Lake (Backcljau) Improvements in explosive gas actuated pump. 

5456. Trewhella Corrugated cylinders for internal combustion engines. 

6093. Bellamy. — Improvements in gas and similar motor engines. 
6204. Sayer.— Improvements in explosive and pressure elastic and non- 
elastic turbine engines. 

6453. Okes Improvements in internal combustion engines. 

6534. Berk Improvements in or connected with gas and oil engines. 

7023. Owen. — Improvements in or in connection with self-generating 

vapour burners, or apparatus for vaporising liquid hydrocarbons 

for heating, lighting, or other purposes. 
7064. Bellamy. — Improvements in gas and similar motor engines. 
7292. Walker. — Exhaust scrubber for petroleum and other motors having 

offensive or injurious exhaust. 
7426. Dawson, — Improvements in gas engines. 



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Appendix II - 531 



NO. 



7433. List and others. —Improvements in and connected with what are 

commonly known as petroleum or oil engines. 
7466. Burt. — Improvements in variable speed and reversing mechanism for 
gas or vapour or other motors. 

8095. Morcom Improvements in working motive power engines, and in 

apparatus actuated by combustible gases to "be employed for that 

purpose, and for other purposes. 
8158. Lindahl. — Improvements in or relating to admission valves for petro- 
leum or similar motors. 
8409. Wilkinson. — Improvements in and relating to gas, oil, and like 

power motors. 
8639. Drake. — Improvements in hydrocarbon engines. 
8864. Robinson, A. E. & II. — Improvements in oil or gas engines. 
8967. Crouan. — Improvements in gas and other motive power engines. 
91 8 1. Abel (Gas-Motoren-Fabrik Deutz). — Improvements in gas and oil 

motor engines. 

9216. Okcs Improvements in internal combustion engines. 

9549. Briickert & Delattre. — Improvements in rotary motors applicable 

also as pumps. 
9618. Roots. — Improvements in internal combustion engines. 
10240. Gessner. — Improvements in steam and other engines and pumps. 
10274. Abel (Gas-Motoren-Fabrik Deutz) — Improvements in valve gear for 

gas and petroleum motor engines. 
10310. Hartley & Kerr. — Improvements in gas and like engines. 
10801. Peebles. — Improvements in or connected with gas or vapour motors. 
12330. Grove.— Improvements in heating lamps applicable to hydrocarbon 

engines, and apparatus therefor. 
12388. List and others. —Improvements in what are commonly known as 

petroleum or oil engines. 
12427. Dougill.— Improvements in gas and explosive vapour motors. 
12600. Drysdale.— Improvements in valves and atomising apparatus for 

hydrocarbon engines. 
12732. Morgan. — Improvements in combustible vapour engines, and in 

their accessories. 
12S43. Priestman, W. D. & S. — Improvements in or applicable to internal 

combustion engines. 
12917. Pullen. — An improved oil, spirit, gas, or steam motor. 
132S2. Furneaux & Butler. — Improvements in starting apparatus for gas and 

other motors. 
1351S. Fiddes, A. & F. A.— Improvements in gas and vapour motor engines 

and the like. 
142 12. Smethurst and others. — Improvements in methods of, and apparatus 

for, applying combustible mixtures of air and gas or inflammable 

vapour to driving motive power engines. 

MM 2 



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532 The Gas Engine 



NO. 



14454. Bickerton. — Improvements in starting apparatus for gas engines. 
14546. Boult (The C.D.M. Niel). — Improvements in or relating to automatic 

starting gear for motors operated by explosion. 
14558. Hornsby & Edwards. — Improvements in engines operated by the 

explosion of mixtures of combustible vapour or gas and air. 
14572. Thompson (Diirr).— New or improved vaporisers for petroleum motors. 
1 489 1. Boult (La S. F. des M. C.).— Improvements in or relating to petro- 
leum, gas, or oil engines. 

l S J 99- Campbell Improvements in oil and gas motor engines. 

15359. Bellamy. — Improvements in travelling cranes. 

15405. Fryer. — Improvements in valve gear for the * Qerk * and like type of 

gas engine in which a separate air and gas pump is employed. 
15900. Boult (Brauer & Windnitz). — Improvements in rotary engines and 

pumps. 
15947. Simms. -Improvements in or connected with whistles or the like for 

explosion engines. 
16072. May bach Improvements in the method of producing the explosive 

mixture in hydrocarbon engines. 
16079. Tipping. — Improvements in rotary pumps, blowers, and engines, 

also applicable for measuring fluids. 
1629^. Qurin.— Adjustable cam. 

1 64 10. Spiel & Spiel. — Improvements in hydrocarbon engines. 
16575. Drake. — Improvements in the vaporisers and ignition tubes of oil 

engines. 

1675 1. Briinler. — Device in gas or petroleum engines with slow combustion 

for insuring the maintenance of the combustion. 

16752. Briinler. —Process for insuring the commencement of the ignition in 

gas and petroleum engines. 
169CO. Crossley & Atkinson. — Improvements in internal combustion engines. 
16985. Maybach.— Improvements in the method of igniting the explosive 

mixture of hydrocarbons. 
17784. Shuttleworth and others. — Improvements in and for connecting 

together lamps and vaporisers. 
18152 Sherrin & Garner. -Improvements in cylinders and pistons for gas 

and other heat engines. 
20007. RyUnd. — Improvements in explosive engines. 
2080S. Priestman, W. D. & S. — Improved means applicable for use in mixing 

liquids with gases in the manufacture of vapour. 
21 120. Hamilton. — Improvements in gas motor engines. 
21775. Briinler. — Process for obtaining a compression in gas and petroleum 

^ engines with slow combustion. 
2190S. Barclay. — Improvements in and relating to sight-feed lubricators. 
22181. Roots. — Improvements in internal combustion engines. 
22753. Pinkney. — Improvements in internal combustion engines* 



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Appendix II 533 

NO. 

2 3°75« Crossley & Atkinson. — Improvements in gas or internal combustion 

engines. 

23175. Stoke. — Outlet valve motion for gas and petroleum engines. 

2 3379- Wattles. — Improvements in gas engines. 

23571. Roots. — Improvements in internal combustion engines. 

23735. Sintz and others. — Improvements in gas and other explosive engines. 

24258. Durand. — Improvements in or relating to explosion engines. 

24384. Hamilton. — Improvements in gas motor engines. 

24584. Crossley & 1 lulley. — Improvements in internal combustion oil engines. 

24612. Sitton. — Improvements in oil engines. 

24666. Campl)cll. —Improvements in gas motor engines. 

1894. 

263. Lindcmann. — Improvements in gas or petroleum motors. 

408. Abel (The Gas-Motorcn-Fabrik Deutz). — Improvements in gas and 

oil motor engines. 
573. Dulier. — A method of and apparatus for generating elastic fluid for 

working engines. 
752. Lake (Die Firma Fried. Krupp). — Improvements relating to distri- 
buting and igniting devices for gas, petroleum, and like engines. 
778. Campl>ell. — Improvements in oil and gas motor engines. 
1 121. Meacock. — Improvements in engine starters. 
1 58 1. Bonier. — Improvements in and relating to gas engines. 
2064. Foster. — Improvements in gas and other internal combustion engines. 
2540. Fidler. — The utilisation of exhaust heat from gas, oil, tar, or spirit 

engines. 
2593. Lake (Grant). — Improvements in gas engines. 
2656. Bellamy. — Improvements in gas and similar motor engines. 
3122. Weyland. — Improvements in vaporisers for petroleum motors. 
3303. Decombe and Lamena. — Improvements in actuating or operating the 

valves of steam and other motive power engines. 
3485. Davy. — Improvements in gas and other internal combustion engines. 
4301. Holt. — A method of working valves of gas and oil motors, and 

apparatus for that purpose. 
4312. A. & F. A. Fiddes. — Improvements in or connected with internal 
combustion motors. 

4959. Singer. — Improvements in gas engine valves. 

4960. Singer. — Improvements in double acting compression gas engines or 

oil engines. 
5218. Rollason.— Improvements in the governing and construction of gas 

engines. 
5493* Southall. — Improvements in gas and oil motor engines. 
5577* Capitaine. — An improved petroleum motor. 



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534 The Gas Engine 



No. 



5680. Brilnler. —Device for injecting the petroleum in four-stroke petro- 

leum engines with two air inlet valves. 

5681. Mitchelmore. — Improvements in hydrocarbon engines. 

5843. Thomson, Yates, J. P. Binns, & II. G. Binns. — Improvements in 

gas and oil engines. 
6122. Hornsby & Edwards. — Improvements in explosion engines. 
6138. Reid (Brayton). — Improvements in oil and gas engines. 
6364. Adams. — Improvements in gas, oil, and steam engines. 
6647. Katon. — An improved combined steam and gas generator and engine. 
6755. I-ow. — Improvements in gas engines. 
7023. Skene. — Improvements in gas and oil vapour engines. 
7294. Farmer. — Improvements in gas and like engines. 
7357- Schwarz. — A new or improved explosion engine. 
7485. Merryweathcr & Jakeman. — Improvements in motor engines to be 

worked with gas or vapour such as petroleum vapour. 
7538. Roots. — Improvements in oil engines. 

7542. Wolfmuller and Geisenhof (amended).— Improvements in and relat- 
ing to motor-propelled velocipedes. 
7630. Butter.— Improvements in means for operating and controlling the 

valves of steam, gas, or oil engines. 
8041. Adams. —Improvements in exploding chambers or receptacles, and 
apparatus connected therewith, for oil, gas, or similar engines, 
motors, or pumps. 
8295. Holt.— Improvements in gas motor or oil motor cars. 
8668. Hojjg & Grove. — Improvements in oil or gas engines. 
9305. Dickinson. — Improvements in or relating to gas or vapour engines. 
9403. Scott.- Improvements in pumps for oil engines or other purposes. 
9723. Sondermann. — Improvements in and connected with the cylinders of 

engines, motors, and compressors. 
9788. BrUnler. — Improvements in petroleum engines. 
9889. J., S., F., & K. Carter.— Improvements in and connected with 

petroleum oil engines. 
10034. Haddan (Piguet & Company).— An improved method of and appara- 
tus for obtaining motive power by means of explosions. 
101 13. Holt. — Improvements in gas motor engines. 

1045 1. Piers.— Improvements in or connected with locomotive engines, or 

other engines subject to intermittent work or varying loads, &c. 

10452. Piers. — Improvements in or connected with locomotive engines, or 

other engines subject to intermittent work or varying loads, &c. 
105 1 1. Thompson (Schoenner). — Improvements in toy motors. 
10623. Gibbon. — Improvements in petroleum or hydrocarbon engines. 
10788. Ilenriod-Sehweizer. — Improvements in gas and hydrocarbon engines 

or motors. 
Ilioi. Howard, Bousfield & Bastin.— Improvements in explosion engines. 



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Appendix II 535 



NO. 



1 1 108. Davis. — Improved starting device for gas and hydrocarbon engines. 

in 19. Lazar, Banki, & Csonka. — A new or improved mixing chamber for 
petroleum and similar engines. 

11261. Hamilton. — Improvements in oil engines. 

1 1 369. Weisman & Holroyd (amended).— Improvements in hydrocarbon 
motors. 

1 1526. Red fern (Nordenfelt & Christophe). — An improved explosion en- 
gine, also adapted to be driven by steam. 

1 1 593. Iladdan (Pons y CureO. — Improvements in or relating to the con- 
struction of pistons and their packings. 

1 1 726. Lamena. — A vapour spring, and improvements in connection with 
the utilisation of the same. 

I1S02. Dawson. — Improvements in gas engines. 

1 1 804. Ganswindt. — Improvements in mechanism for producing rotatory 
motion from reciprocating motion. 

1 1997. Fielding. — Improvements in explosive engines. 

12520. Ewins. — A piston for engines. 

12820. Tyler & De Vesian. — Improvements in apparatus for mixing and 
burning inflammable and explosive gases and vapours. 

12840. Terry.— Improvements in apparatus for cooling circulating water in 
gas and oil and other engines working by explosion, &c. 

12917. Boult (Lausmann). — Improvements in or relating to reversing gear 
for steam and other motors. 

13298. Griffin. — Improvements in gas and oil motor engines. 

13333. Marks (Hirsch). — Improvements in gas engines. 

13524. Vcrmersch. — Improvements in gas engines. 

13546. Burt. — Improvements in apparatus or arrangements for transmitting 
and controlling the power of gas or vapour or other motors. 

13825. Arschauloff. — Improvements in caloric engines. 

13996. Thompson (De l'alacios & Goetjes). — Improvements in the art of 
aerostation and apparatus therefor. 

14002. Holt. — Improvements in gas motor cars. 

14476. Bryant. — A new or improved vapour or gas motor engine. 

1 506 1. Schumacher, Pickering, Whittam, & Platts. — Improvements in or 
relating to hydraulic and other engines. 

1 5109. Schimming. — Improvements in or relating to gas and similar motors. 

1 5152. Faure. — Improvements in the propulsion and construction of veloci- 
pedes and other vehicles. 

15272. Weyman. — Improvements in oil or hydrocarbon engines. 

1 572 1. W. D. & S. Priestman. — Improvements in hydrocarbon engines. 

1623a Saurer-Hauser.— Improvements in heating and igniting devices for 
gas engines. 

1.7233. Knight. — Improvements in oil or hydrocarbon engines. 

17308. Roots.— Improvements in internal combustion engines. 



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536 The Gas Engine 



NO. 



17549. Maccallum. — Improvements in internal combustion engines. 

18443. Terry. — Improvements relating to the use of liquid fuel, and appa- 
ratus for that purpose. 

18452. Bedson & Hamilton. — Improvements applicable to oil engines. 

19894. Harris. — Improvements in high-speed gas engines. 

20123. Shillito (The Lcipziger Dampfmaschinen- und Mctoren-Fabrik). — An 
improved gas and petroleum motor. 

20192. Grove & Hogg. — Improvements in hydrocarbon engines. 

20538. Norris & Henty. — Improvements in hot air engines. 

21032. Duke. — Improvements in the means for automatically lighting gas. 

21829. Abel (The Gas-Motoren-Fabrik Deutz). — Improved method of and 
apparatus for working gas or oil motor engines operating with slow 
combustion. 

22852. Armstrong. — Hand starting gear for gas, oil, and other internal com- 
bustion engines. 

22891. Turner. — Disengaging starting handle for gas and oil engines and 
other motors that are not self-starting. 

22946. Clerk & Lanchester. — Improvements in gas and like engines. 

23028. Robinson. — Improvements in gas and vapour engines. 

23802. Pollock & Whyte. — Improvements in oil engines. 

24089. Marks (Hirsch). — Improvements in gas engines. 

24133. Heys (Letombe). — Improvements in gas and similar engines. 

24239. Withers. — An improved gas engine. 

24898. Hawkins. — An improved explosive for producing motive power, and 
apparatus to be used in connection therewith 

24949. Lindley. —Improvements in and connected with fluid -pressure motors, 

25275. I. & T. W. Cordingley. — Improvements in apparatus for igniting 
the gases in gas engines and the like. 

2 5334- Goddard. — Improvements in threshing machines. 

i8 9S . 

347. Humphrey. — Improvements in gas or oil motor engines. 
' 546. Niemczik. — Ignition- and gas-generating- body for explosive engines 
rendered incandescent by an electric current. 
644. Pinkney. — Improvements in internal combustion engines. 
749. Karavodin. — Improvements in fluid-pressure heat engines. 
946. Marks (Hirsch). — Improvements in gas engines. 
973. Wane & Horsey. — Improved arrangement of appliances connected 

with internal combustion engines. 
1046. Lones. — Improvements in gas steam and com pressed -air engines. 
1071. Boult (Karger). — Improvements in or relating to the cylinders of 

heat engines. 
1310. Hailing & Lindahl. — Improvements in or relating to apparatus for 
controlling the valves of engines. 



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Appendix II 537 



NO. 



1580. Millet. — Improvements in velocipedes. 

1623. Piers. — Improvements in connection with motive power engines for 

driving tramway cars and other vehicles. 
1884. Serret. — Improvements in apparatus for diminishing the noise of 

gases escaping from the exhaust of gas engines and the like. 
1922. Niemczik. — Arrangement for starting gas and petroleum engines. 
2327. Clarke. — Improvements in gas and oil motor valve motion. 
2550. Crastin. — Improvements in or applicable to gas engines. 
2565. Ferranti. — Improvements in steam, hot-air, and other engines. 
2594. Pennink. — A new or improved high and low pressure gas generator. 
2638. James. — Improvements in or appertaining to gas and oil engines. 
2890. Clerk. — Improvements in pneumatic-pressure power hammers. 
3357. Stanley. — Improvements in and relating to explosion engines. 
3638. Crossley.— Improvements in internal combustion oil engines. 
3783. Warner & Rackham. — Improvements in gas motor engines. 
3806. Collis. — Improvements in oil, gas, or vapour engines. 
3923. Wallmann. — Improvements in petroleum and gas motors. 
41 16. J. P. & H. G. Binns. — Improvements in gas and oil engines. 
4243. Diesel. — Improvements in regulating fuel supply for slow combustion 

motors, and apparatus for that purpose. 
4604. Furneaux & Butler. — Improvements in or relating to apparatus for 

starting hydrocarbon and like motor engines. 
4786. Tangyes Limited & Robson. — Improvements in internal combustion 

engines. 
4972. Kol be.— Improvements in fluid-pressure heat engines. 
5373. Johnson (Tower). — Improvements in vehicle motors. 
6151. Wildt. —An improved gas engine. 
6383. Southall. — Improvements in gas and oil motor engines. 
6523. The Brayton Petroleum Motor Co. Ld. & Townsend. — Improve- 
ments in governing apparatus for engines. 
6800. Mackenzie (Crouan). — Improvements in gas engines and the like. 
6972. Donaldson. — Improvements in gas motors. 
6974. Southwell. — Improvements in explosion engines. 
7197. Weatherley. — Improvements in petroleum engines. 
7747. Weatherley. — Improvements in petroleum engines. 
8120. Merichenski & Moffat.— A new or improved apparatus for the pro- 
duction of gas from oil. 
8197. Turner & Harding. — A combined exhaust silencer and circulating 

pump for gas engines. 
8355. Klunzinger. — Ignition apparatus for gas and oil engines. 
8815. Kolbe. — An improved method and means for transmitting or convert- 
ing power or movement, &c. 
8S17. Kolbe. Improvements in or connected with fluid-pressure heat 
engines. 



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538 The Gas Engine 

NO. 

9038. Melhuish. —Improvements in and connected with internal combustion 

engines. 
9188. Fraser. — System or process of heat regeneration and gas manufacture 

for internal combustion engines. 
9922. Berrenberg & Krauss. — Improvements in wheel motors for cycles and 

other similar vehicles. 
9964. Mex. — Improvements in and relating to petroleum motors. 
10245. Williams. — Improvements in blow-lamps. 
1062 1. Pool.— Improvements in oil engines. 
107 10. Bell & Clerk. — Improvements in hydrocarbon motors. 
10758. Abel (The Gas-Motoren-Fabrik Deutz). — A combined locomotive gas 

engine with car. 
1 1 282. Howard & Bousfield. — Improvements in or connected with explosion 

engines. 
1 1400. Duryea. — Improvements in or relating to motor vehicles. 
1 1493. Green. — Improvements in gas motor engines. 
1 1 709. Hewitt. — Improvements in steam, air, and gas rotary engines, and in 

exhaust and compression pumps. 
1 1925. Melhuish & Beaumont. — An improved high speed gas or hydro- 
carbon engine. 
1 1955. Atkinson. — Improvements in internal combustion engines. 
12095. Holt. — Improvements in valve gear for gas or oil motor engines. 
12097. Dawson. — Improvements in oil engines. 
12131. Pennink. — Improvements in or relating to high and low pressure gas 

generators. 
12287. Brayton Petroleum Motor Co. Ld. & Withers. — Improvements in 

petroleum and like engines. 
12306. Diesel. — Improvements in direct combustion motor engines working 

with multiple compression of the air required for combustion. 
12409. Macdonald. — Improvements in motors, especially applicable to 

tramways. 
13047. Compagnon & Guibert. — Improvements in gas or petroleum motors. 
13675. Lorenz. — Improvements in and relating to upright or vertical petro- 
leum motors. 
13975. Spiel. — An improved combined vaporiser and igniter for oil motors. 
14009. Spiel. — Improvements in and connected with the vaporising and 

igniting devices of gas, petroleum, and similar motors. 
14076. Durand. — Improvements in and connected with the inlet valves of 

petroleum-motors. 
14242. Ladd. — Improvements relating to explosion engines and to gas 

generators to be used in connection therewith. 
1 436 1. Lorenz. — Improvements in and relating to hydrocarbon engines 

working in a four-stroke cycle. 
14385. Darr. — Improvements in gas and oil engines. 



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Appendix II 5 39 



NO. 



15045. Lanchester. — Improvements in gas and oil motor engines. 

1 53 10. A. & F. Shuttleworth & Deed. — Improved means for igniting the 

* combustible charges in gas, oil, and like engines. 
1 541 1. Ilinchliffe. — Improvements in and connected with vaporisers of oil 

and other similar engines. 
1 55 14. Day. — Improvements in oil engines. 
15694. Clubbe & Southey.— Improvements in locomotive carriages for 

common roads. 
1606S. Smith. — Improvements in connection with the propulsion of road or 

other vehicles. 
1,6079. Briggs. — Improvements in gas and oil engines or motors. 
16096. Grist. — Improvements in apparatus for vaporising hydrocarbons or 

other volatile liquids, and mixing the vapour with air for use in 

motors. 
161 57. Clubbe & Southey. — Improvements in internal combustion engines. 
16362. Roger. — Improvements in self-propelling vehicles. 
16556. Gass.— Improvements in gas engines. 
16609. Campbell. — Improvements in gas and oil motor engines. 
16703. Weatherhogg. — Improvements in petroleum and similar engines. 
1 6891. White & Middleton. — Improvements in and relating to gas engines. 
17282. Prince. — Improvements in means for propelling vehicles by internal 

combustion motors. * 

1 7315. Duncan, Suberbie, & Michaux. — Improvements in petroleum 

motors adapted for propelling vehicles and for other purposes. 
17560. Iloyle. — A new furnace-gas or heat motor. 
18070. Norris & Ilenty. — Improvements in valve gears for gas, oil, Or other 

engines. 
18379. Johnston. — Improvements in gas and petroleum engines. 
18706. R. D., \V. D., & H. C. Cundall. — Improvements in oil motor 

engines. 
18794. Turnock. — Inprovements in and connected with means for supplying 

and utilising compressed air for motive power and other purposes. 
18908. Lanchester.— Improvements in gas and oil motor engines. 
18995. Southall. — Improvements in operating the valves of gas and oil 

engines. 
1 9142. Grove. —Improvements in oil or gas engines. 
19162. Bethell. — An improved plough. 
19267. Cans. — An improved lighting apparatus for explosive gas mixtures, 

more especially for motors. 
19391. dimming. —Improvements in refrigerating machinery. 
19568. Briinler. — Improvements in explosion engines. 
19700. Gautier & Wehrle. — Improvements in rotary engines and pumps. 
19734. De Dion & Bouton.— Improved means or apparatus for electrically 

igniting and governing petroleum and other like motors. 



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540 The Gas Engine 



NO. 



19735. De Dion & Bouton. — Improvements in motors worked by explosive 

mixtures. 
I9744< Barker — Improvements in or connected with vaporisers for oil 

engines. 
19980. Delahaye. — Improvements in motors worked by petroleum or other 

liquid hydrocarbon. 
20189. Johnston. — Regulating or adjusting the transmission of power and 

speed of prime movers. 
20305. Kane.— Improvements in gas and like engines, and in the method of 

mixing and volatilising the gases in the same. 
2041 1. Erben. — Improvements relating to mechanically propelled vehicles. 
20666. Nunn. —A gas or oil motor mowing machine. 
20703. Lister. — Improvements in gas and like motor engines. 
20705. Bickerton. — Improvements in gas engines. 
20914. Boult (La Societe Francaise dcs Cycles Gladiator). — Improvements 

in or relating to motor vehicles. 
21 315. Allen & Barker. — Improvements in oil and gas engines. 
21484. Enger. — An improved method of and apparatus for governing or 

regulating motors. 
2 1 52 1. Pinckney. — Improvements in and connected with generating steam 

and furnace gases, and for utilising the same for motive purposes. 
21568. Conrad. — Improvements in or relating to explosion engines. 
21574. Fessard. — Improvements in gas and oil engines. 
21594. Green. — Improvements in means for starting explosion engines. 
21774. Magee.— Improvements in and relating to gas engines. 
21912. White. — Improvements in and connected with governors for gas anil 

oil engines. 
21993. Washburn. — Improvements in combined motive power and electric 

generating and storing apparatus for the propulsion of movable 

conveyances and analogous power purposes. 
22161. Prestwick & The Protector Lamp and Lighting Co., Ld.— Im- 
provements in velocipedes and other vehicles. 
22347. Clubl>e & Southey. — Improvements in engines for the propulsion of 

road carriages. 
22402. De Dion & Bouton. — Improvements in motors worked by explosive 

mixtures. 
22523. Hceley, Graves, & Coates.— An apparatus for the immediate stoppage 

of gas or steam engines from any room of the works or factory. 
22690. Marks. — Improvements in gas, oil, and like engines. 
22793. Rowbotham. — Improvements in and relating to motor engines, for 

vehicles and launch propulsion in particular. 
23113. Wise (Buckeye Manufacturing Co.). — Improvements in gas engines. 
23412. Tenting. — Improvements in self-propelling or horseless vehicles, and 

in petroleum motors employed for driving the same. 



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Appendix II 541 



NO. 



23417. De Sales. — Improvements in gas and other like engines. 

23706. Boult (La Societe* Francaise des Cycles Gladiator). — Improvements 
in or relating to motor vehicles. 

23740. Thompson & Webb. — A rotary gas or oil motor for driving tricyles 
or other light vehicles. 

23771. Pennington. — Improvements in self-propelling road vehicles. 

23879. Warsop. — Improvements in oil engines and the like. 

24101. Cooper. — Improvements in driving gear for locomotive carriages. 

2 4 2 35» Brindley, Nay lor, & Wilson. — Improvements in or in and relating to 
self-propelled road vehicles. 

2441 1. Wordsworth, Wiseman, & Holroyd. — Improvements in motors 
worked by hydrocarbon or other gases, and in means for con- 
trolling same. 

24792. Rogers. — Improvements in gas and explosive vapour engines. 

25024. Livingston. — Improvement in engine stops. 

25050. Pennington. — Improvements in and relating to aerial vessels and to 
methods of propelling and controlling the same. 

1896. 
313. Gautier. — Improvements in petroleum motors and the like. 
624. New. — Improvements in gas and oil engines. 
731. Hamilton & Kollason. — Improvements in self-propelled vehicles. 
786. Smith. — Improvements in gas and oil engines, part of the same* l>eing 

applicable to steam engines and the like. 
795. Abel (The Gas-Motoren-Fabrik Deutz). — Means for cooling the inlet 

vavle of gas and oil motor engines. 
884. Capitaine. — An improved mode and mechanism for regulation of the 
temperature of the combustion chamber and vaporiser in petro- 
leum motors. 
996. Pennington. — Improvements in explosion engines. 
1095. Beverley.— Improvements in hydrocarbon and petroleum engines. 
1327. Dougill & Marks.— Improvements in governing-apparatus for engines 

in which gas or vapour and air are used. 
1404. Maxim. — Improvements in the conversion of heat energy into mechani- 
cal energy, and in apparatus therefor. 
1789. Sohnlein.— Improvements in oil, gas, and othsr motive power 

engines. 
2024. Crowden. — Improvements in or relating to explosion motors. 
21 13. Howard & Bousficld. — Improvements in gear for transmitting rotary 

motion. 
2138. Roots. — Improvements in internal combustion engines. 
21 71. Lewis. — Improvements in gas and other such like engine cylinders, 
and in the mode and means for keeping such cylinders from be- 
coming unduly hot. 



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542 The Gas Engine 

NO. 

2290. Lane. — Improvements in gas or petroleum engines, especially applic- 
able to such engines when used for propulsion of vehicles, &c. 

2394. Sturmey. — Improvements in or relating to velocipedes and other 
vehicles, and self-contained motors therefor. 

2436. Maxim. — Improvements in process and in means or apparatus for pro- 
ducing motive power from combustible liquids, gases or vapours. 

2753. Bamford & Wadsworth. — Improvements in gas engines, in part 
applicable to oil and similar engines. 

2S74. Marchant. — Pumps driven by vaporised oil motors. 

2895. Crossley & Atkinson. — Improvements in igniting apparatus for inter- 
nal combustion motors. 

3062. Taylor. — Improvements in oil vaporisers. 

3217. Abel (The Gas-Motoren-Fabrik Deutz). —Improvements in upright 
gas and oil motor engines. 

3331. Reynolds & Astley. — An improved automatic feed for supplying oil 
or other liquids in regulated quantities for burning, lubricating, 
or other purposes. 

3381. Baker.— Improvements in or relating to explosion engines. 

3503. A. & F. Shuttleworth & Deed. — Improvements in the igniting 
arrangements of gas and hydrocarbon engines. 

3696. W. B. & C. S. Brough. — Improvements in motive power engines 
actuated by the explosive force of gases or vapours. 

3798. Carpenter & Allen. — Improvements in cultivators. 

4067. Burne. — Improvements in motive power engines actuated by the 
explosive force of gases or vapours. 

4069. Clubbe & Southcy. — An electric vaporiser for oil engines. 

4153. Bromhead (Kiel). —A double-acting gas engine. 

4184. Kowbotham. — Improvements in gas and like engines, and in the 
method of mixing and volatilising the gases in the same. 

4245. Holt. — Improvements in gas or oil traction cars. 

4492. Martineau. — Improvements in internal combustion engines. 

4618. Mallet. — Improvements in petroleum and like motors. 

4634. Crow.— Improvements in gas, petroleum, and other internal com- 
bustion engines. 

4766. Alston. — Improvements in and relating to compound gas engines. 

4924. Simpson. — Improvements in gas and other hydrocarbon engines. 

4938. Wenham. — Improvements in engines worked by combustible gases or 
vapours, more especially intended for propelling vehicles. 

5277. Donaldson. — Improvements in the gas control of an explosive gas 
motor. 

5598. Thompson. — Improvements in or relating to apparatus applicable for 
braking and starting oil, gas, and other engines, also machinery, 
tramcars, and other vehicles. 

5814. Lanchcster. —Improvements in gas and oil motors. 



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Appendix II 543 

NO. 

5860. Ledin. — Improvements in and relating to motors actuated by pro- 
ducts of combustion mixed with steam. 

6067. Briggs. — Improvements in or connected with gas and oil engines or 
motors and carriages propelled thereby. 

6073. Cook. — Improvements in and connected with means for generating 
combustion products under pressure, and utilising the same for 
operating heat engines and for propelling ships. 

6378. Adorjan. — Improved valve motion and engine for highly superheated 
steam or gas. 

6573. Dowsing & Keating. — An improvement in engines worked by gas or 
combustible vapour. 

6590. Hall. — Improvements in or relating to variable speed apparatus for 
transmitting power. 

6718. Prince. — Improvements in and connected with internal combustion 
motors. 

6738. W. D. & S. Priestman & Richardson. — Improved means applicable 
for use in igniting the working charge in hydrocarburetted-air 
engines. 

6740. Ibbett. — Improvements in gas, oil, or hydrocarlxm vapour engines. 

6834. (jascoine & Courtois. — Improvements in horseless carriages. 

6872. Pinkert. — New or improved motor for propelling and manoeuvring 
vessels. 

6915. Milder brand.— Improvements in or relating to motor cycles and 
the like 

6933. Hornsby, Edwards, Roberts, & Young. — Improvements in explosion 
engines. 

6974. J* S., R. D., W. D., & II. C. Cundall. — Improvements in motor 
engines operated by oil, gas, and other explosive matter. 

7036. Duryea. — Improvements in or relating to gas and like motors. 

7147. Auriol. — Improvements in gas and oil engines. 

7250. Bousfield (La Societe des Procedes Desgoflfe et de Georges). — Im- 
provements in centrifugal pumps and motors. 

7454. Berrcnberg. — Improvements in the construction of motor engines, and 
their application in the propulsion of autocars and road -carriages. 

7543. Best. — Improvements in petroleum engines. 

7549. Pennington. — Improvements in starting devices for motors. 

7566. Riib. —Improvements in motor-driven velocipedes. 

7603. Lanchester. — Improvements in gas and other motive power engines. " 

7609. Tavernier. — A new or improved motor actuated by explosions. 

7822. Bickerton. — Improvements in oil engines. 

7825. Clark.— Improvements in apparatus for compressing air. 

7940. Simms (Maybach). — Improvements in or in connection with petro- 
leum burners for heating purposes. 

8089. Seek. — Improved outlet-valve motion for gas and oil engines. 



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544 The Gas Engine 



NO. 



8255. Dale. — Improvements in mechanical motors driven by steam, com- 
pressed air, mixtures of gas and air, petroleum and air, or other 
explosive mixtures. 

8306. Bollee. — Improvements in or relating to self-propelled vehicles. 

8359- MacDonald.— Improvements in and connected with motor power 
apparatus for propelling vehicles and boats. 

8813. Bickerton. — Improvements in gas and oil engines. 

8918. Young (Gardner). — Improvements in explosion engines. 

9052. Loyal. — Improvements in petroleum and like motors. 

9092. Tubb & Mondey. —Improvements in and relating to oil, gas, and 
vapour engines. 

9143. Carse. — Improvements relating to motor-driven vehicles. 

9199. McGhee. — Improvements in the valves and valve gear of gas or 
internal combustion motor engines. 

9256. Tetter. — Improvements in or relating to the arrangements of the £.ir 
and exhaust valves of internal combustion engines. 

9259. Boult (Landry & Beyroux). — Improvements in or relating to explo- 
sion engines. 

9336. I)e Dion & Bouton. — Improvements in explosion motors. 

9337. De Dion & Bouton. — Improvements in the valvular arrangement of 

petroleum and like engines. 
9526. Maxim. — Improvements in and relating to oil and gas engines. 
9571. De Chasseloup-Laubat. — Improvements in steam, gas, and other 

engines. 
9732. De Dion & Bouton. — Improvement in or connected with explosion 

motors. 
9770. Hockett. — Gas engine. 

9982. Lane. — Improvements in gas, oil, or other internal combustion 
engines or motors. 

1 00 1 8. Lane. — Improvements in or connected with motive power apparatus 
consuming liquid fuel, such as petroleum and heavy oils. 

10141. Mors. — Improvements in and relating to self-propelled vehicles. 

1 01 64. Duncan.— Improvements in and relating to the driving of light vehicles. 

I0 3°7- J* P» & H« G. Binns. — Improvements in gas and oil engines. 

10399. Bennett & Thomas. — Improvements in gas, oil, and spirit engines. 

10424. Simms. — Improvements in cooling the surfaces of the cylinders of 
explosively driven engines by means of air. 

I0690. Tangyes Ld. & Rol>son. — New or improved mechanism for revers- 
ing and stopping oil, gas, or other motors driven by machinery or 
apparatus. 

1 1 058. Clubbe, Southey, & the Electric Motive Power Co., Ld. — Improve- 
ments in motor cars or autocars, applicable also to launches. 

1 1078. Peugeot.— Improvements in oil engines. 

1 1088. Gans. — Improvements relating to igniters for the motors of auto- 
motive vehicles and feed vessels therefor. 



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Appendix II 545 



NO. 



1 1 209. Bomborn. — Improvements in vaporisers for petroleum engines. 
1 1 307. Day. — Improvements in and connected with gas and oil engines. 
11342, Faure. — Improvements in or connected with motor-driven road 

vehicles. 
1 1 347. Wiseman & Holroyd. — Improvements in hydrocarbon motors. 
1 1 35 1 . Hayward. — Improvements in rotary engines. 
1 1 41 4. Barker. — Improvements in fog or audible signalling apparatus for 

lighthouses and the like. 
1 1475. Longuemare. — Improvements in burners for petroleum and other 

vapours. 
11481. Tomlinson. — Improvements in the driving of machinery, vehicles, 
boats, and the like, by electro-motors or other high-speed motors. 
1 1 49 1. Holden. — Improvements in the construction of internal combustion 

engines for propelling carriages, cycles, and boats. 
1 1 506. Magee. — Improvements in and connected with railway vehicles and 

road vehicles driven by means of oil motors. 
1 1 549. Hamerschlag. — Improvements in igniting devices for gas and petro- 
leum engines. 
1 1 573. Haddan (De Coninck). — Improvements in and relating to auto- 
motive vehicles. 
11914. Lutzmann. — Improvements in and connected with motor- propelled 

vehicles. 
1 1992. Polke. — Improved cam mechanism. 
12003. Abel (The Gas-Motoren-Fabrik Deutz). — Appliance employed in 

starting gas and ofl motor engines. 
1 204 1. Smith. — Improvements in road motor cars and in machinery for the 

same. 
12274. Hunter. — Improvements in internal combustion motors for use in the 
propulsion of automobile vehicles and water craft and for general 
purposes. 
12337. British Motor Syndicate, Ld. (Maybach) Improvements in port- 
able engines. 
12446. J., S., F., & E. Carter. — Improvements in explosion engines. 
12539. Paget.— Improvements in and connected with fly-wheels for motor- 
cars. 
12633. J. A. & W. Drake. — Improvements in oil or gas engines. 
12758. Crouan. — Improvements in motive power engines driven by gas or 

inflammable vapour. 
12776. Hilderbrand. — An improved carburettor or gas-producer. 
12805. Altham. — Improvements in oil engines. 

12943. Rowbotham. — Improvements in gas-generating apparatus for explo- 
sion engines. 
13833. Young (Gardner). — Improvements in and relating to igniters for ex- 
plosion engines or motors. 

N N 



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546 The Gas Engine 



NO. 



13864. Audin.— Improvements in gas or petroleum engines. 

1 42 1 2. Wood. — Improvements in explosion engines. 

1 42 1 3. Peugeot. — A new system of air carburettor. 

14375- W. & C. S. Gowlland. — Improvements in and connected with means 

for the utilisation of acetylene gas in motors and ordnance, and fur 

producing explosions and for other purposes. 
14446. W. & C. S. Gowlland. — Improvements in or relating to fluid- pressure 

motors. 
14639. Dowsing. — Improvements in apparatus' or the production of electri- 
city from the waste heat of gas, steam, or other heat engines. 
1473 1. Wilson. — Improvements in the vaporising and igniting devices of 

petroleum engines. 
14756. Roots. — Improvements in or connected with oil engines for pro- 

. pelling carriages, boats, and the like. 
14829. Rowbotham.— Improvements in vaporising arrangements for oil or 

inflammable vapour engines. 
14959. Merrit & Naismith. — Improvements in internal combustion engines. 
15045. Baker. — Improvements in gas or vapour engines. 
1 5127. Melhuish. — Improvements in and relating to the construction and 

arrangement of gear for regulating or automatically controlling the 

speed and power of internal combustion engines, &c. 
1 5197. Heys (Heilmann). — Improvements in oil and gas engines. 
15267. Stilwell. — Improvements in engines operated by gas, vapour, oil, or 

the like. 
15279. Rowbotham. — Improvements in vaporising apparatus for explosion 

engines. 
15752. Gowlland. — Improved method of obtaining motive power from 

gaseous pressure, and apparatus therefor. 
16067. Banks. — Improvements in oil motors, specially applicable to cycles. 
1627 7 A. Pratis & Marengo. — The utilisation of hydrogen gas for the obtain- 

ment of light, heat, and power. 
16348. Gordon. — Improvements in ignition apparatus for explosive engines. 
16366. G. G. & R. O. Blakey. — Improvements in gas and other explosive 

engines. 
16465. Bollee. — Improvements in or relating to motor or self-propelled road 

vehicles. 
16512. Singer. — Improvements in internal combustion or detonating engines. 
16630. Bectz.— Improvements in rotary explosion engines or motors. 
16660. Bennett & Thomas. — Improvements in oil and spirit engines. 
16708. Hunt. — Improvements in regulating apparatus for gas motor engines. 
16997. Lacasse. — New or improved horseless carriage. 
17203. Gale & Thompson. — Improvements in methodsand means for electric 

regulation of power. 
1 722 1. Gautier & Wehrll. — Improvements in and relating to motor vehicles. 



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Appendix II 547 



NO. 



17448. Jahn. — Improved starting apparatus for gas engines and the like. 

17573. Pennington.— Improvements in or relating to the ignition of the 
charge in explosion, oil, and like engines. 

17926. Reynolds.— An improved explosion motor for cycles, vehicles, and 
vessels. 

1 805 1. Holt.— Improvements in gas or oil motor tramcars and similar 
vehicles. 

1 8 194. Golby (Kumpf.). — Improvements in hydrocarbon motors. 

18202. Huskisson. — Improvements in and relating to rotary turbine engines. 

18294. Abel (The Gas-Motoren-Fabrik Deutz).— Method for starting gas and 
oil motor engines with twin cylinders. 

18304. Bromhead (Neil).— A double-acting or duplex oil engine. 

18520. Dunkley. — Improvements in motor carriages. 

18551. Clubbe, Southey, & the Electric Motive Power Co. Ld.— Im- 
provements in and relating to the suspension or supporting of 
engines on motor carriages. 

18585. Arrol & Johnston. — Improvements in oil or gas motors for wheeled 
vehicles and for general purposes. 

18783. Austin. — Improvements in mechanically propelled road vehicles. 

18829. Lanchester. — Improvements in the igniting arrangements of gas and 
oil motor engines. 

1 883 1. Stephens. — Improvements in oil engines for marine and vehicular 
propulsion. 

1898S. Edwards (C. & J. Kiister). — Improvements in apparatus for equalis- 
ing the pressure upon the crankpins of steam and other engines. 

19061. Bergmann & Vollmer. — Improvements in or appertaining to autocars 
and the like. 

1 91 36. Grelet. —An improved explosion motor. 

19211. Prince, Smith & Monkhouse. — Improvements in internal com- 
bustion motors. 

19232. Smith. — Improved means for lessening vibration in reciprocating 
engines and machines. 

20428. Roger. — Improvements in gas and oil motors for autocars. 

20449. Smith. — Improvements in lubricating the cylinders, pistons, and 
valves of gas engines. 

20655. Wilkinson. — Improvements in gas, oil, and like engines for autocars, 
also applicable for other suitable purposes. 

21 136. Lister. — Improved oil or gas engine applicable for use in the pro- 
pulsion of vehicles. 

21274. Mundcn. — Improvements in motor vehicles. 

21587. Faure. — Improvements in hot-air engines. 

21675. Johnson. — Improvements in and connected with motor carriages. 

21743. Martel. — Improvements in the construction of hydrocarburetted-air 
engines, and in their application to tram and other road vehicles. 

N N 2 



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543 The Gas Engine 

HO. 

21877. Hornsby& Sons, Ld. (Burton).— Speed regulating mechanism of 

petroleum and other motors. 
22064. Bayer. — Improvements in rotary engines. 
22376. Southall. — Improvements in oil engines. 
22527. Gibbon. — Improvements in explosion engines. 
22935. Lanchester. — Improvements in gas and oil motor engines. 
23005. Quentin. — Improvements in and relating to hydrocarbon vapourmotois. 
231 10. Tangye & Johnson. — Anew or improved gas and oil or petroleum 

engine. 
23138. Lones. — An improved gas engine, convertible into an oil engine or 

vice versa. 
23142. Fetavel. — Revolving cylinder oil or gas engine. 
23270. Fctreano. — Apparatus for vaporising hydrocarbons, applicable to 

engines worked by gas, petroleum, alcohol, and the like. 
23296. The Motive Tower & Light Co. Ld. & Friend. — Improvements 

in hydrocarbon motors. 
23306. Auge. — Improvements in explosive engines. 
23350. — Arrol & Johnston. — Improvements in apparatus for forming anJ 

regulating the combination of oil with air for oil motors. 
23462. Wisch. — Reversing-gear for explosion motors. 
23492. Monin & Perot. — Improvements in and relating to gas and petroleum 

motors. 
23604. Roots & Venables. — Improvements in or connected with oil motors 

for vehicles, cycles, boats, and the like. 
23802. O'Brien (Triouleyre). — Improvements in autocars. 
23860. Swiderski & Schwicker. — Self-heating vaporiser for mineral oil 

motors. 
24091. Dawes. — Improvements in internal combustion engines. 
24144. Thompson (Pillon & Le Melle). — Improved balanced motor engine. 
2431 1. Dawes. — Improvements in internal combustion engines. 
24457. W. D. & S. Priestman. — Improvements in igniting devices for 

hydrocarburetted-air engines. 
24550. Gathmann. — Improvements in rotary gas and oil engines. 
24656. Bickerton. — Improvements relating to the utilisation of waste gases 

from gas engines for heating purposes. 
24793. Crastin. — Improvements in or connected with apparatus for vapor* 

ising oil. 

24804. Ide. — Improvements in steam, gas, or other engines. 

24805. Lanchester.— Improvements in the igniting arrangements of gas and 

oil motor engines. 
24858. Caldwell. — An improved governor, especially applicable to gas 

engines and the like. 
24881. Furneaux & Butler. — Improvements in explosion engines special!}' 

suitable for propelling vehicles, boats, and other bodies. 



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Appendix II 549 



NO. 



24905. Nayler. — Improvements in vaporisers for oil motors. 

24994. Oechelhaeuser. — Improvements in high-pressure gas engines. 

25558. Arnold. — Improvements in the method and means for discharging the 
vapour generated in the water jackets of gas and oil engines. 

25642. Smith. — Improved apparatus for silencing the exhaust in gas or other 
engines. 

26233. Allen & Barker. — Improvements in oil and gas engines. 

26261. Mewburn (Bates). — Improvements in and in connection with the 
manufacture of combustible gas, including illuminating gas, and in 
apparatus or plant for the purpose. 

26292. Baines & Norris. — Improvements in engine lubricators, in part applic- 
able to oil-feeding appliances for oil engines. 

2^399. Read & Turner. — Improvements in gas and oil engines. 

26638. Allsop. — Improvements in gas and petroleum engines and motors. 

26879. Power. — Improvements in governing oil, gas, and vapour engines. 

27184. Simpson. — Improvements in motor-driven vehicles. 

27207. Pennington. — Improvements in the electric ignition of charges in 

explosion engines. 

27208. Pennington. — Improvements in means for suppressing the noise of 

the exhaust from internal combustion engines. 
27276. Middleton. — Improvements in motor wheels or mechanical tractors. 
27408. James. —Improvements in engine 'exhausts.' 
27535. Payne. — Improvements in hydrocarbon and other vapour motors. 
27568. Johnson. — Improvements in oil and gas motors. 

27602. Holden. — Improvements in the construction of internal combustion 

engines in combination with cycles or carriages. 

27603. Holden. — Improvements in the construction of internal combustion 

engines in combination with cycles or carriages. 

27979. Thomson. — Improvements in apparatus for deriving, controlling, and 
regulating motive power from gas or oil engines for various pur- 
poses. 

281 17. Lyon. — Improved means or apparatus for igniting explosive gases in 
petroleum and other like motors. 

28514. Tomlinson. — Improvements in and relating to internal combustion 
and compressed-air engines. 

28523. Dutton. — Improvements in oil, gas, and analogous motors. 

28527. Mackenzie & Carling. — Improvements in gas or oil motor engines, 
also applicable to steam or other fluid -pressure engines. 

28583. Lepape. — A new or improved cooler for petroleum motors. 

28648. Balzer & Humphrey. — Improvements in motors or engines. 

28842. Culver. — Improvements in gas engines. 

28867. Geisenhof. — An improved motor-van. 

28892. Wood.— Improvements in valve gear for gas or oil engines. 

28979. Koser & Mazurier. — Improvements in and relating to gas or petro- 
leum and like motors. 



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550 The Gas Engine 

' NO. 

29067. Turner. — An improved silent condenser for gas and like engines. 

29578. Bryan. — Improvements in combined internal combustion and com- 
pressed gas or air engines. 

29610. Jones. — Improvements in and pertaining to motors adapted to te 
worked by pressure of fluid, such as a combustible mixture of petro- 
leum vapour, or gas with air, or analogous motive fluid. 

29718. Hardingham (Webster). — Improvements in rotary engines, applicable 
for use as motors, pumps, blowers, or the like. 

29747. Higgini, Bessemer, & Nicholson. — Improvements relating to engines 
or motors and to the application of the same for the propulsion ot 
vehicles. 

29S54. L'Homme. — Improvements in explosion engines or motors. 

29858. Altmann. — Improved method and apparatus for burning liquid fuel. 

30010. Potter. — Improvements in engines actuated by oil, petroleum, spirit, 
or other gas-generating liquids. 

30026. I. & T. W. Cordingley & Smith. — Improvements in oil motors. 

30045. Toll. — Improvements in or relating to the valve mechanism of explo- 
sion engines. 

30075. Marsden. — Improvements in oil or liquid hydrocarbon motors. 

30133. Askham. — Improved apparatus applicable to gas engines. 

30162. Romer & Perkes. — Improvements in explosive gas motors. 

1897. 

95. Dagnall. — Improvements in internal combustion engines. 
659. Rub. — Improvements relating to the igniting devices of the motors 

of motor cycles. 
679. Lister. — Improvements appertaining to oil engines. 
736. M. H. C. & R. E. C. Shann. — Improvements in or relating to ex- 
plosion engines. 
746. Gautier & Wehrle. — Improvements in carburetting-apparatus. 
878. Philippot. — An improved atomising device for petroleum and other 
motors. 
. 900. Winton. — Improvements in explosion engines. 
913. Norgrove, Westwood, J. & J. C. Bates, Poultney, & R. H. Bates. 
— Improvements in or relating to vaporisers for oil engines and 
the like. 
1 01 1. Wimshurst. — Improvements in gas and explosive vapour engines. 
1 160. Lake (La Societe* Fritscher & Houdry). — Improvements in gas and 

petroleum engines. 
1400. Dougill. — Improvements in or relating to motor engines worked by 

gas or other combustible vapours. 
1402. Hunter. — Improvements in gas or oil engines. 
1475. Poron. — Improvements in motor engines and gear for autocars. 



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Appendix II 551 

K0. 

1598, Winton. — Improvements in explosion engines. 
1652. Conrad. — An apparatus for governing the valve gear of hydrocarbon 
motors. 

1694. Winton.— Improvements in explosion engines. 

1695. Winton. —Improvements in explosion engines. 
2095. Holt. — A regulator of the circulation of cooling water. 

2123. Martindale. — Improvements in motors operated by fluid or gaseous 

pressure. 
2595. Ringelmann. — Improved means for exploding combustible mixtures, 

and utilising the explosive force thereof for driving rotary 

engines. 
2666. Johnson. — Improvements in and connected with the generating and 

transmission of power for driving tramway carriages and other 

road vehicles and for other purposes. 
2849. Stroh. — Starting device for oil engines. 
3025. Maxim. — Improvements in cooling devices for gas, oil, and steam 

and similar engines. 
3370. Crossley. — Improvements in internal combustion motors. 
3890. Auriol. — Improvements in gas engines. 
4299. Patcrson. — Improvements in and connected with petroleum and like 

engines for motor cars and other purposes. 
4528. Calcy & Stephenson. — Improvements in gas, oil, and other ex- 
plosion engines. 
4556. Pennington. -•improvements in or relating to the cooling of cylinders 

of explosion engines. 
4580. Ollivier. — Improvements relating to explosion engines. 
4605. Ball. — Improvements in and relating to oil and gas engines. 
4610. Embleton. — Improvements in explosion motors. 
4640. Vallec. — Autocar with special petroleum motor. 
4879. Prentice. — Improvements in steam, gas, and other engines. 
4888. Ollivier. — Improvements in gas, petroleum, or like motors. 
4963. Hamilton. — Improvements in steam, gas, and air engines. 
5147. Rolfe & Hornby. — Improvements in and connected with explosion 

engines. 
5522. Brewer (Nicolas). — Improvements in or connected with gas or 

internal combustion motors. 
5526. Clubbe, Southcy, & The Electric Motive Power Co. Ld.— A firing 

device for internal combustion engines. 
5618. Bowden & Urquart.— Improvements in or connected with internal 

combustion engines working with liquid hydrocarbon and air. 
5736. Lees. — Improvements applicable to explosion engines. 
5882. Roots & Verablcs. — Improvements in petrocars or motor vehicles. 
6035. Dunsmore. — Improvements in and relating to gas and oil engines. 
6645. Tournet. — Certain improvements in oil and gas engines. 



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552 Tlie Gas Engine 



NO. 

6651. Hargrcaves. — Improvements in or relating to internal combustion 

engines. 
6688. Myers. — Improvements connected with explosive vapour power 

engines. 
7074. Rowden. — Improvements in apparatus for igniting the compressed 

charges in gas or oil motors. 
7098. Reeve. — Improvements in and relating to gas or liquid fuel engines. 
7333. Le Brun. — Improvements in gas, petroleum, or like motors. 
7526. Sundberg. — Improvements in regulating devices for gas and petro- 
leum engines. 
777a Baincs & Norris.— Improvements in oil engines. 
7785. Banki & Csonka. — Improvements in automatic igniting apparatus for 

gas and petroleum motors, 
7969. Longuemare. — Improvements in carburettors for explosion engines. 
7979. Martindale. — Improvements in rotary engines. 
8056. Putsch. — Improvements in or relating to gas engines. 
8064. Marks (Bouvier). — Improvements in vaporisers for oil motors. 
8100. Shann. — Improvements in or relating to internal explosion engines. 
83 1 8. Pinkney. — Improvements in oil engines. 
8471. Royer. — Improved means for cooling the water or condensing the 

steam from the motors of motor-cars. 
8529. Dougill & Marks. — Improvements in gas, oil, and like engines. 
8547' Thornton & Pollard. — Improvements in motors worked with heated 

compressed air, in parts applicable to internfl combustion engines. 
8822. Wimshurst. — An improvement in gas or oil engines. 
9002. Erie. — Improvements in motor road vehicles. 
9098. Sciitz & Heydemeyer. — Improvements in or relating to apparatus for 

starting gas engines or the like. 
9389. Baker. — Improvements in gas engines. 
9463. Klaus. — Improvements in motor or self-propelled vehicles. 
9722. Roots & Venables. — Improvements in and connected with oil motors 

for vehicles and propelling generally. 
9784. Grivel. — Improvements in and relating to carburetting apparatus, 

particularly applicable to petroleum engines, oil engines, and the 

like. 
9907. Peugeot. — An improvement in oil engines. 

9929. Buck & Torrey. — Improvements in apparatus for carburetting air. 
9963. Grivel. — Improvements in carburetting air or internal combustion 

engines, particularly adapted for the propulsion of motor cars and 

other vehicles. 
10005. Fritscher & Houdry. — Improvements in gas or hydrocarbon motors. 
10097. Henroid-Schweizer. — Improvements in internal combustion engines. 
10261. Boult (Lefebvre). — Improvements in or relating to apparatus for 

carburetting air. 



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Appendix II 



553 



NO. 

105 1 9. Johnson. — Improvement in and connected with oil and other ex- 
plosion motors for the purpose of reducing the smell and visible 
vapour of or from the exhaust. 
10620. Maxim. — Improvements in aerial or flying machines. 
1 1015. Marks (Chaudun). — Improvements in rotary motors. 
1 1 334. Vaughan-Sherrin. — Improvements in electric ignition devices for 

gas engines and other gaseous explosive mixture engines. 
11414. Baker & Oflen. — Improvements in gear for converting reciprocating 

motion into rotary in engines and other machines. 
1152a Mitchell. — Improvements in rotary engines. 
1 1547. Casley & Woodman. — Improvements in hydrocarbon motors. 
11619. Pilcher. — Improvements in and connected with engines actuated by 

mixed products of combustion and steam. 
ir7io. Boult (La Societe Anonyme d'Automobilisme et de Cyclisme). — 

Improvements in or relating to oil and similar motors. 
1 1 801. Fielding. — An improved vaporising and igniting device for gas and 

oil motor engines. 
1 1930. Esteve. — Improved mineral oil engine. 

1 1 95 1. Lamy & Richard. — Improvements in or relating to internal com- 
bustion engines or motors. 
12050. Fairhurst. — Improvements in motive power engines actuated by the 

explosive force of gases or vapours. 
121 17. Pool. — Improvements in explosion engines. 
1 2 199. Johnson. — Improvements in and connected with fluid -pressure 

apparatus for generating, storing, and transmitting power. 
12553. Rossel. — Improvements in petroleum and like motors. 
12924. Thompson (Loutzky). — An improved four-stroke cycle motor for 

bicycles and the like. 
1 2942 A. Johnson. — Improvements in electrical igniting apparatus for explosion 

engines and for other purposes. 
12954. Simms. — Improvements in cooling the surfaces of the cylinders of 

explosively driven engines. 
13092. Allsop. — Starting gas and petroleum engines and motors. 
1 3 16 1. Calloch. — Improvements in internal combustion engines. 
13325. Letombe. — Improvements in and relating to gas engines. 
I 35 I 7- Westinghouse & Ruud. — Improvements in gas engines. 
1 372 1. Straker, Caird, & Rayner. — Improvements in oil motor engines. 
*3734« Lake (La Societe Main Ciiusti & Co.) — An improved explosion 

engine, more especially applicable to the propulsion of vehicles. 
139S8. Hunt. — Improvements in vaporisers and igniters for oil motor 

engines, partly applicable to gas motor engines. 
14165. Barnes. — Improvements in internal combustion engines using hydro- 
carbon as fuel. 
14298. Smith. — Gas motors with differential cyclinders. 



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554 The Gas Engine 



NO. 



X 4397* Wattles. —Improvements in the generation and utilisation of hydrogen 
gas and electricity for motive power, lighting and healing pur- 
poses. 

14455. Capel. — Improvements in gas engines. 

14649. De la Croix. — Improvements in motor cycles. 

148 14. White (Brown). — An improved method of apparatus for generating 
motive power by explosions. 

14826. Hall. — Improvements in or relating to power-transmission apparatus. 

15233. Duryea. — Improvements in hydrocarbon or gas engines. 

1534S. Simms.— -Improvements in or connected with the exhaust valves of 
explosion engines. 

15354. Boult (Chaudun). — Improvements in or relating to rotary motors. 

1 54 1 1. Bosch. — Improved electric igniter for gas engines. 

15822. Crozct. — Improvements in or connected with cylinder and piston 
motors. 

15908. Katz. — Improvements in or relating to explosion motors. 

15980. Sello, Schaefer & Lehmbeck. — Improvements in oil and gas engines. 

15983. Uhlenhuth. — Improvements in internal combustion engines. 

16074. Gallice. — Motor engine worked by explosive fluid mixtures. 

16380. Ricci. — Improved mechanism for regulating the ignition point in oil 
and other motors. 

16399. Bracklow.— Improvements in or relating to gas and oil motors. 

1641 1. Seunier. — An improved hydrocarbon motor. 

1663 1. Russ. — Improvements in and relating to gas engines. 

16705. Calloch. — A new or improved motor car. 

16729. New. — Improvements in heavy -oil engines. 

16943. Robinson & Molyneux. — Improvements in pistons. 

16977. Jones. — Improvements in means for heating the ignition device for 
gas, oil, or spirit engines. 

1 7 127. Petreano. — Improvements in and connected with gas and hydro- 
car bon engines. 

17204. Southall. — Improvements in gas and oil motor engines. 

1 73 1 7. Petreano & Bonnet. — Improvements in and connected with gas and 
hydrocarlwn engines. 

17839. Hornsby & Edwards. — Improvements in or connected with explosion 
engines. 

17842. Marconnet. — Improvements in or connected with apparatus for the 
generation of gaseous fluid pressure. 

18005. Thompson (Julien). — Improvements in and relating to apparatus for 
producing gas suitable for heating, motive power, or lighting pur- 
poses by the aid of volatile hydrocarbons. 

1821a E., T. H., & L. Gardner. — Improvements in or relating to oil motors. 

1 853 1. Lawson. — Improvements in or relating to motors, especially suitable 
for the propulsion of motor road vehicles. 



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Appendix II 555 



NO. 



18546. Tomlinson. — Improvements in and relating to internal combustion 
or explosive engines. 

18804. Petreano. — Improvements in means for reversing gas and hydro- 
carbon (petroleum) motors. 

1S940. Martini & Deimel. — Improvements in gas ignition apparatus. 

19533. Haddan (Heinle & Wegelin). — Improvements in gas motors. 

19534. Haddan (Heinle & Wegelin). — Improvements in lubricating devices 

for motor cycles. 

19642. Dymond (Meyer). — Improved process for attaining a very high 
ignition temperature in hydrocarbon engines. 

19673. Hayot. — Improvements in gas turbines. 

1 99 10. Rowden. — Improvements in internal combustion engines. 

19936. O'Donnel (De Bouilhac). — Improvements in and relating to motor 
cars. 

201 16. Cail. — Improvements in or relating to internal combustion engines or 
motors. 

20135. Dymond (Diirr). — Improvements in hydrocarbon locomotives. 

20236. J. F. & R. H. Shaw. — An improved method for supplying lubri- 
cating oil in regular quantities for gas and oil engines and the like, 
and for supplying in regular quantities combustible liquids for 
driving purposes. 

20269. Cordonnier. — New or improved rotary motor. 

20389. Firman & Cave. — Improvements in explosion engines. 

20455. Jensen (C. & A. White). — An electric igniter for internal combustion 
engines. 

20617. Martha. — Improvements in gas, petroleum or mineral-oil motors. 

20761. Roots. — Improvements in internal combustion engines. 

20801. Edmondson & Dawson. — Improvements in the method of and means 
employed for starting internal combustion engines. 

20880. Ironmonger. — Improvements in rotary engines actuated by steam or 
other expansive gases. 

21329. Dutton. — Improvements in oil, gas, and analogous motors 

21738. Bomborn. — Improvements in fuel-feeding devices for petroleum 
motors and similar combustion engines. 

21833. Scott & Hawkins. — Improvements in and relating to the generation 
of gas for motive power, illuminating, heating, and other purposes. 

22065. Dymond. — Improvements in gas burners suitable for use in incan- 
descent gas lighting and for other purposes. 

22310. Pinkney. — Improvements in fluid -pressure heat motors. 

22564. Fistie. — Improvements in gas engines. 

22971. Leigh (Gossel in) —Improvements in motors driven by combustible 
petroleum or any other suitable gas or vapour. 

23357. Simpson. — Improvements in and connected with internal com- 
bustion motors. 



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556 The Gas Engine 



NO. 



23361. Thompson (De Von). — Improvements in and relating to gas 
engines. 

23S41. Cribbes & Ross. — A new or improved means of obviating or sup- 
pressing the noise caused from the exhaust gases escaping from 
gas or other engines, and apparatus connected therewith. 

23582. W. D. & S. Priestman & Richardson.— Improvements in the work- 
ing of internal combustion engines. 

23622. Rowlingson (La Societe Diligeon et Cie). — Improved cooling 
arrangement for internal combustion engines, specially applicable to 
motor road vehicles. 

24096. Weiss & Mietz. — Improvements in and connected with explosion 
engines. 

24432. Mason & Rixson. — Improved water regulator for heat in gas engine 
water tanks. 

24712. Doolittle (Still & Bengough). — Improvements in or pertaining to 
motor apparatus suitable for propelling carriages, cycles, and other 
road vehicles, or for light power purposes generally. 

24861. E., T. II., & L. Gardner. — New or improved feed mechanism for 
internal combustion engines. 

25581. Crouan. — A lighting regulator for gas and petroleum motors, lighting 

electrically. 

25582. Crouan. — Electric lighter for gas and petroleum motors. 

25856. Hesketh & Marcet. — New or improved means for generating gaseous 

products of combustion under pressure, for operating engines or for 

other purposes. 
25987. Hamilton. — Improvements in gas and similar engines. 
26898. Iden. — Improvements in spirit or light-oil motors for vehicles and 

the like. 
271 12. Crouan. — New system of regulator for gas and petroleum motors. 
27301. Ravel. — Improvements in gas and like engines. 
27315. Rowbotham. — Improvements in explosion engines. 
28390. Boult (Rumpf). — Improvements in or relating to internal combustion 

engines. 
28821. Thompson (Irgens & Brunn). — Improvements in and connected with 

rotary motors. 
28918. Turrell & Lawson. — Improvements in or relating to motor vehicles. 
29074. Brillil. — Improvements in explosion motors. 
29361. Kerridge. — Improvements in or relating to electric gas-lighting and 

controlling devices. 

29467. New. — Improvements in the ignition arrangements of explosion 

engines. 

29468. New. — Improvements in explosion engines. 

29508. Huber. — Method and apparatus for utilising steam and combustion 
gases at very high pressures as motive power. 



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Appendix II 557 

NO. ( 

29567. Boult (Dusaulx.) — Improvements in or relating to carburettors lor 

oil motors. 
29593- Lloyd.— Improvements in and relating to explosion engines. 
30106. Chauveau.— Apparatus for mixing the explosive charge of internal 

combustion engines. 
30182. Conrad.— Improvements in balancing devices for power engines 

with thnist crank driving. 
30266. Johnson. — Motor car. 



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558 



NAME INDEX 

TO 

GAS AND OIL ENGINE PATENTS 

1791-1897 INCLUSIVE 



ABE 

Abfx. C. D. (Bcissel), 1882—3435 
(Daimler), 1879—3245; 1880 — 

343 

(Langcn & Otto), 1866—434; 

1867 — 2245 

(Daimler), 1874—414, 605 ; 

1875—71 

(Gas-Motoren-Fabrik Dcutz), 

18S5— 11933; 1886—5804; 1887— 
847, ii8q. 11503, 12187, 17188, 
17896; 1888—688, 3020, 3095, 
5724, 9602, 14349; 1889—5616, 
18746, 20892; 1891 — 1903, 6717, 
8469. 14519, i77 2 4. 22847; 1892— 
2728, 13204; 1893—735, 9181, 
10274; 1894—408, 21829; 1895 — 
10758 ; 1896—795. 3217, 12003, 
18294 

(Otto). 1875—3615 ; 1876— 

2081; 1878— 1770; 1881— 60; 
188.1—1677 

(Spiel), 1 88 1 — 4244 

Adam, 1887—1266 

Adams, 1891—741; 1892—6828; 
1894 —6364, 8041 

Adorjan, 1896—6378 

Aeugonheyster, 1888 — 13414 

Ainswortti, 1884—8960 

Alexander, E. P. , 1875—4342 ; 1879— • 

3905 
Alleock, 1881—565 
Allen and another, 1895—21315; 

1896—3798, 26233 
Allison (McNctt), 1889— 12045 
AIlsop, 1897 — 13092, 26638 
Alston, 1896 — 4766 



AUG 

Altham, 1896— 12805 

Altmann, 1888 — 8317; 1891 — 7157; 

1892—21534 ; 1896—29858 
Anderson, J., 1854 — 191 ; 1859 — 2767 ; 

1866—3363 ; 1 87 1— 2326 ; 1882— 

1754; 1887—15010 
Anderson, 1888 — 14248, 17413 ; 1S92 

—12165 
Andrew, 1883— 1010, 3066, 4201 ; 

1884— 1322 1 ; 1885—5561 ; 1892— 

17227, 20802, 20803 
Angele, 1879—3905 
Antisell & Bruce, 1875—2016 
Arbos. J., 1862—3108 
Archat, 1887 — 91 11 
Archibald, C. D., 1858—996 
Aria, 1888—9342 
Armstrong, 1894 — 22852 
Arnold, 1896—25558 
Arrol and another, 1896 — 18585, 

23350 
Arschauloff, 1894—13825 
Ashbury and others, 1882— 5188 
Ashcr, 1885 — 1424 
Ashworth, 1891— 18020 
Askham, 1896-30133 
Astlcy and another, 1896—3331 
Atkinson, 1879—3213; 1881 -40S6; 

1882-4378, 4388; 1884-3039. 

16404; 1885-2712, 3785, 15243; 

1886—3522; 1887— 1 191 1 ; 1889- 

20482; 1892— 2181, 2492; 1893 — 

16900, 23075; 1895-11955; 1896— 

2895 
Audin, 1896— 13864 
Auge, 1896—23306 



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Name Index 



559 



AUR 

Auriol, 1896 -7147; 1897—3890 
Austin, 1896 -18783 
Aylesbury, 1880 -351 2 

Babacci, G. B., 1868— 1393 

Babbitt, 1867 -3690 

Babcock, 1886-478 

Backeljau, 1884 - 11361 ; 1893 -5256 

Haines and another, 1896—26292 ; 

1897-7770 
Bainford, 1887—2236 
Baker, 1896-33C1, 15045; 1897 — 

9389 
Baldwin, 1882— 4886; 1890-12678 
Balestrins, H., 1855 — ion 
Ball, 1897-4605 

Balzer and another, 1896-28648 
Bamford and another, 1896—2753 
Banki, 1889 -6296 
Banki and others, 1894— 11119 
Banki and another, 1897-7785 
Banks, 1896 -16067 
Barber, J., 1791 -1833 
Barclay, 1891 - 6578 ; 1893— 21908 
Barker, 1887 - 14027 ; 1888 — 1 1242 ; 

1892 - 1879 ; 1895 - 19744 ; 1896 — 

11414 
Barker and another, 1895-21315; 

1896 -26233 
Barnes, 1897-14165 
Harnett, W., 1838-7615 
Barnett, 1889— 18847 
Baron, 1879-2 
Barrett, 1 891— 8251 
Barron, 1878— 1170; 1891—19318 
Barsanti & Matieucci, 1854—1072; 

1857-1655; 1861 -3270 
Bastin and others, 1894— iiioi 
Bates, 1896 -26261 
Bates, J., J. C, and R. H., and 

others, 1897 -913 
Bauer and another, 1881 — 1074 
Baxter (Hoist), 1890-5005 
Bayer, 1896 —22064 
Beaumont and another, 1895 — 11925 
Bechfeld, 1887— 14952 
Beck. 1881— 5534 
Bectz, 1896 - 16630 
Bedson and another, 1894—18452 
Beechy, 1880 -1653, 4270; 1881 — 

2961; 1882-1318; 1885-3199; 

1887 -4160, 8818 ; 1890—10089 
Beissel, 1882—3435 
Bell, 1892 -4347, 5972 
Bell and another, 1895— 10710 
Bellamy, 1892— 17277, 20802, 20803; 

*893 -45 6 4. 6093, 7064, 15199; 

1894-2656 



BOU 



. Bellini & Carobbi, 1874-961 
Benger, 1888 -5204 
Bengough and another, 1897-24712 
Benier, 1881—1541, 4589; 1882 - 

1868; 1884-16131; 1887 — 1262; 

1894 -158 1 
Bennett and another, 1882— 6136; 

1887— 1 1567 ; 1896 - 10399, 16660 
Benson (Rider), 1879-2191; 1880 — 

425° 

Benz & Co., 1884-9949 ; 1886-5789 

Bergl, 1893—3292 

Bergman n and another, 1896— 1906 1 

Berk, 1894-6534 

Bernadi. 1886—5665 

Bernstein, 1884 -1457 

Berrenbcrg, 1896—7454 

Berrcnberg and another, 1895 - 9922 

Bessemer, H., 1869— 1435 
, Bessemer and others, 1896—29747 
'Best, 1892-24065; 1896-7543 

Bethell, 1895— 19162 

Beugger, 1892-8538, 9439 

Beverley, 1896—1095 

Beyroux and another, 1896 - 9259 

Bickerton, 1880 -4643 ; 188 1 - 1363 ; 
1885— 5519. 15845; 1887-17896; 
1891—227, 297, 6090 

— and another, 1882-2345; 1892 - 
4078; 1893-14454; 1895-20705; 
1896 -8813, 7822, 24656 

Bilbault, 1892-5740 

Binney, 1886—15319; 1888 -10667; 

14076 ; 1889 —14868 ; 1890 — 7146 ; 

15994 ; 1892 - 3909, 22664 
Binns, J. P. and H. G., 1895— 41 16 ; 

1896- 10307 

and others, 1894 -5843 

Bisschop, 1872 -1594 ; 1882—579 

Black, 1885 -14574 

Blakey. G. G. and R. O., 1896- 

16366 
Blancbard, F. B., 1855 339 
Bland, 1892 260 
Blosing, 1888-1381 
Blyth, 1887-516 
Bobrownicki, 1866—181 
Bollee, 1896 -8306, 16465 
Bolt, 1886 -11576 
Bolton, R. L., 1853—515 
Bomborn, 1896 - 11209; 1897-21738 
Bonnet and another, 1897 -17317 
Bosch, 1897- 15411 
Bosshardt (Huntington), 1891-9268 
Boult (Larrivel & Aeugenheyster), 

1888 -13414 

— ( Berliner Maschinenbau Actien 
Gesellschaft), 1891 -383 



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The Gas Engine 



BOU 



BUT 



Boult (Braucr & Windisch), 1893— 
15900 

— (Capitaine), 1888—15840, 15841, 
15845, 15846 

— (Charter), 1892—12183 

— (Compagnie des Moteurs Niel), 
1893 -14546 

— (Lausmann), 1894— 12917 

— ( La Societe* Frar^aise des Cycles 
Gladiator), 1895 — 20914, 2 37°° 

— (Karger), 1895— 1071 

— (Landry & Beyroux), 1896-9259 

— \\& Scici6t6 Anonvmc d'Automo- 
bilisme et de Cytiisme), 1897 — 
11710 

— (Lefebvre), 1897— 10261 

— 1 Chaudun). 1897 -15354 

— 1 Dusaulx), 1897-29567 

— i Rumpf). 1897 -28390 

— 1 La Societe des Moteurs Crebes- 
sac), 1893— 14891 

— (Rotten), 1889 -17024 

— (Sharpneck), 1890— 18645 

— (Levasseur), 1891 — 9006 
Boulton, M. P. W., 1864 -1009, 1291, 

1636,3044; 1865-501, 827, 1915. 

1092; 1866-738; 1868— 1988 ; 

1876—2288, 3620, 3767; 1877 — 

766 ; 1878—2278, 2525, 2609, 2707 ; 

1879—495 ; 1881— 1202, 1389, 3367 ; 

1886 2653 
Bouneville, H. A., 1867 — 1575 
Bourne, J., 1868 -1878, 3594 ; 1869 — 

3705; 1870 -1859 
Bousfield and another, 1833—388; 

1895-11282; 1896-2113 
Bousfield and others, 1894 — iiioi 
Bousfield (La Soci(*t£ des Proc^des 

Desgofle et de Georges), 1896 — 

7250 
Bouton and another, 1895 — x 9734« 

22402; 1896-9337,9732 
Bouvier, 1897 — 8064 
Bowden and another, 1897— 5618 
Bower & Hollingshead, 1868—2808 
Boys, 1886 — 10332 
Bracklow, 1897 — 16399 
Bradford, 1892 — 3156 
Bradley, 1892 — 2862 
Braham and another, 1882 — 2751 
Brandon, A. H., 1869 — 3178 
Brauer, 1893— 15900 
Brayton, 1874—2209; 1890 — 11062; 

1894—6138 
Brayton Petroleum Motor Co. Ld. 

and another, 1895—6523, 12287 
Brcittmayer, 1880 — 3140 ; 1887— 

16257 



Brewer (Xicolas), 1897—5522 

Brie* 1892 — 919 

Bnggs, 1892—16365 ; 1895— 16079 ; 

1896-6067 
Brightmorc, 1888 — 4057 
Brillie. 1807—2074 
Brindley (Naylor & Wilson), 1895 — 

24235 
Brine, 1884 — T2312 ; 1886 — 942 
Brinn, Q. L., 1875 — 3*74 
Brinns, 1800 — 4362 ; 1892— 13859 
Briscall, 1883 — 5 oao 
British Motor Syndicate Ld. (May- 
bach), 1896 — 12337 
Bromhead '(Neil), 18*6 — 4153, 

18304 
Brooks, 1892 — 1246 
Broom an, R. A., 1863 — 2098 
Brough, W. B. & C. S., 1806—3696 
Browett, 1884 — 14341 ; 1887 — 2520, 

1 1345; 188C— 7547, 16057; 1889— 

18847 
Brown, 1825 — 5150 ; 1826—5^50 ; 

1846—11072; 1882—1874; 1897 — 

14814 
Bruce & Antisell, 1875—2016 
Bruckert, 1893—9549 
Brtinler, 1886— 2 140 ; 1892—7047, 

16379, 16380, 16381, 16382; 1893 — 

16751, 16752, 21175; 1894 — 5680, 

9780; 1895—19568 
Brunn and another, 1897—28821 
Brutton, 1889— 6161 
Bryan, 1896 — 29578 
Bryant, 1984—14476 
Brydges, 1881 — 3330 
Buck and another, 1897— 0429 
Buckeye Manufacturing Co., 1895—* 

231 13 
Bull. 1883— 5 1 13 ; 1887— 10202 ; 

1889 — 10634 
Bullock, 1883—5085 
Burgh, 1885— 15194 
Burnc, 1896—4067 
Burt, 1887—11678 ; 1888—3427 ; 

1890—12690; 1891— 19086, 22578; 

1893—1277,7466; 1894 -13546 
Burton, 1896 -21877 
Buss, 1875-1933 
Butcher, 1879 -2618, 4377; 1880 — 

474; 1881-3786; 1883-1835; 

1884— 5641 
Butler, 1887 -15508; 1888—1780, 

1781 ; 1890-6990 

— and others, 1839—9203; 1893— 
13282 

Butter, 1894-7630 

— and another, 1896—24881 



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Name Index 



561 



BUT 



CRO 



Butterworth, E., 1874—1652; 1884- 

1 1086; 1886 — 207,7936, 12134 
Buttress, 1885— 1424 
Byerley & Collins, 1838— 7871 



Cail, 1897— 201 16 

Caird and others, 1897 — 13721 

Caldwell, 1896-24858 

Caley and another, 1897—4528 

Calloch, 1897 — 13 161, 16705 

Campbell, 1883— 5951 ; 1885—6990; 

1888— 10748; 1891— 4355; 1893- 

15199, 24666; 1894-778; 1895- 

16609 
Capel. 1897 -14455 
Capell, 1883 -911 
Capitaine, 1888—15840, 15841, 15845, 

15846; 1891-8069; 1892—6872; 

1894-5577; 1896-884 

— (Benz & Co.), 1884—9949 

— & Brilnler, 1885— 7500, 7581; 
1886 -2140 

Carling, 1891 — no; 1896—28527 

Carpenter and another, 1896 — 3798 

Carosis, A., 1853— 1671 

Carrobbi & Bellini, 1874 — 961 

Carse, 1806— 9143 

Carter, J., S., F., & E., 1894—9889: 

1896—12446 
Casley and another, 1897— n 547 
Casper (Tavernier), 1887—4757 ; 1888 

—5628 ; 1889—7069 ; 1890— 1586 
Casson, 1878 — 3774 
Cattrall, 1885—11555 
Cave and another,* 1897—20389 
Charon, 1888 —12399 
Charter, 1887-1168, 12749; 1892^ 

12183 
Chasseloup-Laubat, 1896— 9571 
Chatterton, 1892 - 6284 
Chaudun, 1897 -15354 
Chauveau, 1897— 30106 
Chemin, 1888 - 9342 
Christophe and another, 1894— 1 1526 
Clark, A. M. (Hurcourt), 1868-354 

(Lesnard), 1869 - 1748 

(Fell), 1879 -1996 

(Kabath), 1883-999 

(Laurent), i882-6n6 

Clark, W., 1858-969 

(Merlanchon), 1863 — 1449 

(Bobrownicki), 1866 — 181 

Clark ( Economic Motor Co.), 1883^ 

4260; 1885-11294, 12483 

.(Hopkins), 1884— 11837 

Clark, M. E., 1896 -7825 
Clarke, T. A. W., 1895—2327 



Clayton, 1878-2037; 1879—3140-; 
1880 -4075 ; 1882 - 2203 ; 1884 — 

a854 
Clerk, D., 1877-252; 1878-3045; 

1879-2424; 1881— 1089; 1882 - 

4048 ; 1883—4046 ; 18C6 -12912 ; 

1889—8805; 1891-12413, 16404, 

18788; 1892—5445,11936, 13117; 

1895-2890 
Clerk and another, 1894—22946; 

t 895— 10710 
Clerk and others, 188 1—3536 
Cliff and another. 1883 - 638 
Clubbe and another, 1895— 15694, 

16157,22347; 1896-4069 
Clubbe and others, 1896—11058, 

18551; 1897-5526 
Coates, 1890—6910; 1891— 18276 
Coates and others, 1895-22523 
Cobham and another, 1884-3495 
Cock, 1892 -18513 
Coffev, 1891—3350 
Cohade, H. F., 1860-1585 
Collins and Byerley, 1838 - 7871 
Collis, 1895 -3806 
Colton (Hartig), 1885-9801 
Compagnon and another, 1895 — 

13047 
Connelly, 1890—5621 ; 1891— 14002 
Conrad, 1895—21568; 1897—1652, 

30182 
Cook, 1896—6073 
Cooke, 1883-326 
Cooper, 1 89 1 -4771 ; 1895— 24101 
Cordenons, 1889-6748 
Cordingley, J. & T. W., 1894^ 

25275 ; 1896 - 30026 
Cordonnier, 1897-20269 
Cormack, W., 1846— n 245 
Courtney (Brunler), 1892- 7047 
Courtois and another, 1896-6834 
Cousins and another, 1879-4101 
Covert, 1889 -12472, 20249; 1891— 

9931 

Crastin, 1895-2550; 1896-24793 

Crebassac, 1893 - 14891 

Cribbes and another, 1897—23541 

Crist, 1889-20249 

Cropper, 1878 3444 

Cross 1 ey , 1 876 - 1 32 ; x 880 —4297 ; 
1881 '-2227; 1882-4489; 1883- 
1722, 3079; 1884-4777, 1 1578; 
1885 -8134; 1886 -11285; 1887 - 
5833; 1888-1705, 3756, 4624; 
1895 -363 8 ; 1897-3370 

— and another, 1878 — 5113; 1879— 
1912, 4499; 1880 341 1 ; 188 1 — 
370, 3450. 54^ ; 1882-1754. 3449; 
O O 



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562 



T/ie Gas Engine 



CRO 



DUN 



1884—3537, 15311 ; 1887— 15010; 

1888—14248, 17413; 1891— 10298; 

1892 -2862 ; 1893 -16900, 23075, 

24584; 1896-2895 
Crossley, F. W., 1874—3205 
and W. J., 1875— 3221 ; 1877— 

2177 
Crotian, 1893—8967; 1895-6800; 

1896—12758; 1897— 25581, 25582, 

27112' 
Cro*', 1896—4634 
Crowdcn, 1896 -2024 
Crowe and others, 1883—2706 ; 1889 

—7594 
Crozet, 1897 — 15822 
Cruikshank (White), 1890—16301 
Csonka, 1889 -6296 
Csonka and another, 1897—7785 
Csonka and others, 1894— 11119 
Culver, 1896 -28842 
dimming, 1895 -19391 
Cundall, J. S., R. D., W. D., & H. C, 

1896-6974 
Cundall, R. D., W. D., & H. C. f 

1895 18706 
Cunynghame, 1886 -10332 
Czermac, 1892 -3292 



D AON ALL, T897-95 

Daimler, 1874 414, 605; 1875—71; 

1879 -3245 ; 1883 -5784 ; 1885 - 

4315,10786; 1885-13163; 1886 — 

14034 ; 1889 — 10007 
Dale, 1896-8255 
Dalton and another, 1879—3467 
Daly, 1889-18847 
Davcy, 1882-2527, 3787 
Davies, 1883-781 
Davis, 1894 -inoS 
Davy, 1884—12264 ; 1886—3473 ; 
. 1887—7677, 13916, 15658; 1892 — 

13077; 1893 -3401, 4696; 1894- 

3485 
Dawes, 1891—4034; 1896—24091, 

2431 1 
Dawson, 1885-7920; 1886—4460; 

1887-6501; 1890—6407; 1891 — 

9865; 1892-6952; 1893-1070, 

7426; 1894 -1 1802; 1895— 12097 
Dawson and another, 1897 -20831 
Day, 1891—6410, 9247; 1895 — 

15514; 1896-11307 
Deacon, 1886 -3010 
De Itouilhac, 1897 —19936 
Deboatteville & Malandin, 1884 — 

3986, 6652, 15248; 1885-15710; 



1886—11 ; 1888 — 2805, 8300, 9249; 

1890— 14900 
Decombe and another, 1894 — 3303 
De Coninck. 1896 — 11573 
De Dion and another, 1895 — 19734. 

19735. 22402; 1896-9337, 9732 
Deed and others, 1896-3503 
Deimel and another, 1897—18940 
De la Croix, 1897— 14649 
Delahaye, 1895-19980 
Dellatre. 1893 -9549 
De Palacios and another, 1894 — 

13996 
De Sales, 1895 -23417 
De Vesian and another, 1894—13820 
De Von, 1897 -23361 
Dewhurst, 1884 -5412 
Dheyne and others, 1890—5933. 

15525 
Dickinson. 1894 -9305 
Dickson, J. F., 1875-744 
Diederichs, 1889 -14926 
Diesel, 1892-7241; 1895—4243, 

12306 
Diligeon & Cie. 1897 —23622 
Dinsmore, 1885 -13309 
Dixon. 1893 -21 10 
Donald, 1879 -540 
Donaldson, 1895 ~ 6972 ; 1806 ^5277 
Doolittle (Still & Bengough), 1897 - 

24712 
Dorrington, 1890 - 6910 ; 1891 —18276 
Dougill, 1881— 2122 ; 1883 -3097 ; 

1884-12318; 1887-10360; 1888 - 

9587; 1893 -12427; 1897 -1400 
Dougill and another, 1896-1327; 

1897-8529 
Douglas, J. C, 1835-6O75; 1384 - 

1 1750 
Dowie, 1892-20088 
Dowsing and another, 1897-6573. 

14639 
Drake, 1893 —16675 (s** cnte) 
Drake, J. A. & \Y\, 1896-12633 
Drake and another, 1881-4407; 

1882— 1717; 1891 -13640, 21015. 

21229; 1892—11141,11708,22797 

1893-8639 
Drysdalc, 1893—12600 
Ducretet, 1887 9717 
Duerr, 1889 -20161 
Dufrene and others, 1882 —1868 
Duke, 1804 -2 1032 
Dulier. 1894-573 
Duncan, 1896 -10164 
Duncan and others, 1895—17315 
Dunkley, 1896 18520 
Dunsmore, 1897-6035 



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Name Index 



563 



DUR 



GAS 



Durand, 1888-6088; 1893-24258; 

1895 -14076 
Duric, 1892—7943, 23800 
Diirr, 1892— 2195a ; 1893— 14572 ; 

1895—14385; 1897 -20135. 
Duryea, 1 895 — 1 1400 ; 1896 - 7036 ; 

1897 -15233 
Dusnulx and others, 1897 -29567 
Dutton, 1896— 28523; 1897— 21329 
Dutton (Spiel), 1883 -4008 
Dymond, 1897—22065 
Dymond (Meyer), 1897— 19642 
Dyson, 1882 -5527 



Earnshaw, 1891— 18715 

Katon, 1894—6647 

Economic Motor Co., 1883 -4260 

Edington, J. C, 1854-549 

Edison, 1883— 1019 

Edmonds (Francois), 1879—4820 

Edmondson and another, 1897— 

20801 
Edwards and others, 1896 -6933 
Edwards, 1880-760; 1881 -1765; 

1891 —17073 ; 1892— 8128, 11962; 

1893 -14^58 
Ed wards ( Petit & Bland), 1892 -260 
— (C. J. KUster), 1896 -i8q88 
Electric Motive Power Co., Lcl., 

1896—11058,18551; 18Q7--5526 
Ellerbcck & Syers, 1875 -4326 
Ellis, 1892 — 20660 
Ellis and another, 188 1 —1409 
Embleton. 1887-11717; 1897— 4610 
Emery, 1867-571 
Emmet, 1882 -397 
Emmet and another, 1879— 4101 
Enger, 1892— 21475 
Erben, 1895—20411 
Erie. 1897 - 9002 
Estevc, 1897 -1 1930 
Eteve and another, 1881— 3113; 

1884 -2135 
Euger, 1895— 21484 
Evans, 1891— 17815; 1893—2788 
Evers. 1 891— 17364 
Ewins, 1894 — 12520 
Ewins and another, 1881—1388 



Faber. 1887-7350 
Fachris, 189 1—5663 
Fairfax, 1884— 13573 
— (Sohnlein), 1892 -1739X 
Fairhurst, 1897— 12050 



Fainveather (Babcock), 1886—478 

Farmer, 1894—7294 

Faure, 1894—15x52; 1896—11342. 

21587 
Ferranti, 1895—2565 
Fessard, 1895—21574 
Fiddes, 1880—5219; 1891—10333; 

1893 -135 18 
Fiddes, A. and F. A., 1894—4312 
Fidlcr, 1894-2540 
Fielding, 1881 - 532 ; 1882 -004 ; 

1883-3070; 1884-2933; 1880 

3402, 9563; 1890-6912; 1891 - 

19517 ; 1893 -108 ; 1894 -11997 ; 

1897 — 11801 
Firman and another, 1807 —20389 
Firma Fried. Krupp, 1894 -752 
Firth, W., 1870 — 2554 
Fischinger, 1890 -7177 
Fistie, 1897 -22561, 22564 
Fogarty, 1873—3848 
Forbes, 1892 -14650 
Ford. S., 1874—486; 1881— 22C0 ; 

1889 — 20115 
Forest, 1883-19 
Forrest, 1891— 22559 
Foster, 1872 -387 ; 1894—2064 
Foulis, 1878—4630, 4843 ; 1879 - 

2073. 4755: 1880—2422, 5090; 

1881—180; 1883—3280 
Francois, 1878— 2474 ; 1879—4820 
Franklin & Dubois, 1869 -1375 
Eraser, 1895 -9188 
Frederking* 1889 -20166 
Friend. 1888 -11614 
Fritscher and another, 1897— 10005 
Fryer, 1893 -15405 
Furneaux, 1803 13282 
P'urneaux and anotlier, 1895—4604; 

1896-24881 



Gale and another, 1806 -17203 
Galhce. 1891 22559; 1897 -10074 
(ialt. 1887 -1168, 12749 
Gambardella, P.. 1850 1345 
Gans, 1895 -19267; 1896 -11088 
Ganwindt. 1894 -11804 
Gardie, 1883 -3383 ; 1886 -61 6i ; 

1888 -2^49; 1892 164 1 3 
Gardner, 1896 -8918, 13833 
Gardner and others, 1897-24861, 

18210 
Garner, 1803— 18152 
Garrett, 1885 -4684 
Garsidr. 1802 17277 
Gas-Motoren-Fabrik Dcutz, The. 1885 

—1 1933; 1887 847, 1189, 11503. 
2 



Digitized by 



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564 



The Gas Engine 



GAS 



HAN 



12187, 17108, 17896; 1888—688, 

3020, 3095, 5724. 9&*. 14349; 

1889—5616, 18746, 20892; 1890 - 

1943, 4164; 1891—1903, 6717, 

8469, 14519. 17724. 2*847 ; 1892 - 

2728 ; 1 893 - 735, 91 8 1 , 10274 ; 

1894-408, 21829; 1895—10758; 

1896-795. 3217. 18294 
Gascoine and another, 1896—6834 
Gasc, 1888 -3964, 6036 
Gass, 1895 — 16556 
Gathmann, 1896-24550 
(jrautier, 1896-313 
Gamier and another, 1895— 19700; 

1896-17221; 1897—746 
Gavillet, 1887-2194 
Gcclgc, \V. E.. 1865-2600; 1867— 

3237 
— - (Marti & Quaglis), 1883— 

5042 
Geisenberger. 1880—533 
Gcisenhof. 1896 28867 
Gcisenhof and another, 1894—7542 
Genty, 1 891 - 14209 ; 1 892 - 8678 
George, R., 1866 3125 
Gessner, 1893— 10240 
Gibbon, 1892— 11962; 1894—10623; 

1896 -22527 
Gilbert-Russell, 1892— 181 18 
Gill, J., 1868 -2264 
Gillespie and another, 1884—3495 

1886—6612 

Gillott, 1885 - 11558 

Gilman & Sowerby, 1825—5150 

Girardet, 1889 -16393 

Gladiator, La Societd Francaise des 

Cycles, 1895 -20914, 23706 
Glaser, 1879 -3732 ; 1882 - 2008 
Glazebrook, J., 1797—2164 

1801—2504 

Goddard, 1894—25334 

Goetjcs and another, 1894—13996 

Golby and another, 1896 — 18194 

Goodrich, 1872 - 3641 

Gottheil, R., 1874 25 

Gordon, 1806 -16348 

Gosselin, 1897 — 22791 

Gowlland, 1896 15752 

Gowlland, W. & C. £>., 1896 — 14375, 

14446 
Graddon, 1879—1161, 4483; 1880^ 

5479; 1881-799 
Grant, 1894-2593 
Graves and others, 1895-22523 
Gray, 1885 -15194 ; 1891— 191, 2053 
Green, 1884 8489 ; 1889 -16202 ; 

1895 -1 1493, 21594 
Grelet, 1896— 19136 



Griffin, 1881—5483; 1883—4080; 

1884—3758, 11576, 14311; 1886 - 

15764; 1887-3934, 10460; 1890- 

6217, 10952, 19962; 1891-4535; 

1892-8733, 16339; 1894-13298 
Griffith, 1884— 12201 
Grist, 1895—16096 
Grivel, 1897-9784, 9963 
Grob, 1890-2919, 10718; 1891^ 

8821, 9323. 14269 
' Groth, 1881 -1382 
— ( Daimler), 1883 -5784 ; 1884 - 

91 12; 1885—13163 
Grove, 1893-12330; 1895— 19142 
Grove and another, 1894—8668, 

20192 
Guibert and another. 1895—13047 
Guillery, 1892-9121 
Guthrie. 1882 — 2337 ; 1884—9001, 

10483 
Gwynne and another, 1 881— 1409 



IIaddan (Schiltz), 1883-4455 
(Gavillet & Martaresche), 

1887 -2194 

(Archat), 1887— 9111 

(Piquet & Co.), 1894 -10034 

(Pons y Curet), 1894—11593 

(De Coninck), 1896—11573 

(Heinle & Wegelin) 1897 — 

19533. 19534 
Haedick, 1889—17008 
Hahn, 1887—10176 
Haigh and another, 1880—1969 ; 

1881-811; 1882-614; 1883- 

25«7 
Hale, 1883 -2192 
Haley & Mills, 1875-265; 1877— 

3024 
Hall, 1890—14382 ; 1896-6590* 

11549; 1897-14826 
Hallewell, R., 1875-2826; 1876 — 

4987. 4988; 1877-81